Graded as an instrument: how accurately it measures, and whether measuring it changes anything.

The accuracy problem with pulse oximetry is a safety problem rather than a nuance. These devices read high in people with darker skin: pooled bias is about 1.1% for high skin pigmentation and 1.5% in people described as Black or African American, and in a meta-analysis of 23 studies the accuracy root-mean-square exceeded the FDA's 3% threshold in every pigmentation group tested. That matters because occult hypoxemia - a reassuring-looking reading sitting over a genuinely low arterial saturation - is about 1.7 times more common in Black than in White hospitalised patients. All of that evidence comes from hospitals, where readings are checked against arterial blood; there is none from home or outpatient settings, and consumer wrist-worn oximeters are sold as wellness products without the clearance a hospital oximeter carries, with no mass-market wrist device meeting the medical standard for pulse oximeters. No trial shows that a well person checking their oxygen saturation at home changes any outcome, and the failure mode worth naming is the one that causes harm: a falsely reassuring number in someone who is genuinely short of breath.

If you use one, sit still, warm your hands, remove nail polish, and take the reading at rest - cold fingers and motion are the commonest causes of a wrong number. Track the trend rather than a single value, and never let a normal reading override how you actually feel.

In a prospective validation against arterial blood-gas co-oximetry under controlled hypoxia, a wrist-worn reflective oximeter showed a bias of only 0.98% (95% CI 0.65-1.32).


Curated grade based on the human and mechanistic evidence for this compound.

The exposure science is solid: showering demonstrably delivers chlorine and trihalomethanes through skin and lungs, and long-term high THM exposure is associated with bladder cancer. But no study has shown that a shower filter improves any health endpoint - benefit claims rest on plausible exposure reduction, and the benefits of water disinfection are widely regarded as outweighing these risks.

After a normal shower, breath chloroform rose to 6-21 µg/m³, and the dermal dose absorbed during showering was approximately equal to the inhaled dose.

Risk analysis : an official publication of the Society for Risk Analysis


Pooled trial data show modest, real short-term pain relief, but certainty is low-to-moderate, heterogeneity is high, and at least one condition-specific meta-analysis (chronic low back pain) is negative. Effects are transient and symptomatic; TENS is very safe but does not modify underlying disease.

transcutaneous electrical nerve stimulation for acute and chronic pain in adults


Standard over-the-counter doses did not prevent cardiovascular events or cancer in large trials (VITAL, STRENGTH) and meta-analyses, though triglyceride lowering is real. Doses above 1 g/day carry a genuine atrial-fibrillation signal - about 13% higher incident risk in a large cohort of healthy users.

Typical studied range 0.5-4 g/day EPA+DHA; triglyceride and blood-pressure effects are dose-dependent, clearest around 2-3 g/day. Event-reduction evidence is for prescription 4 g/day purified EPA in high-risk patients.

Omega-3 fatty acids reduced cardiovascular mortality and improved cardiovascular outcomes


Small, mostly industry-linked split-face trials show modest improvements in photoaging appearance and barrier function. The skin-cancer chemoprevention data are for ORAL nicotinamide, not a topical serum - and the randomized-trial benefit waned after stopping.

Topical 2-5%; most positive trials used 4-5% over 8-12 weeks.

reductions in fine lines and wrinkles, hyperpigmented spots and skin sallowness


A vehicle-controlled trial and human biopsy data show real but modest, cumulative improvement in photoaging signs. Irritation and increased photosensitivity are the main trade-offs, and unsupervised high-strength peels can cause chemical burns. Benefits are cosmetic; not proven to affect longevity.

Leave-on serums and creams typically 4-10% glycolic acid; professional peels of 20-70% are a separate, higher-risk class

In a 22-week double-blind vehicle-controlled trial of 74 patients, an 8% glycolic acid cream modestly but significantly improved overall photodamage severity and sallowness versus vehicle (P<.05).


Trials and meta-analyses show modest improvements in insomnia severity and anxiety, mainly in people with psychiatric conditions; benefits for objectively measured sleep and for children with autism are weak or absent. Effect sizes in healthy general-population sleepers are less certain. No serious adverse events reported.

weighted blankets are an effective and safe intervention for insomnia


The link between low indoor humidity and dryness symptoms, impaired airway defense and virus transmission is well supported, and 40-60% RH is the consensus target. But interventional evidence is thin: a Cochrane review found only low-certainty benefit from humidification itself, and there are no outcome trials of humidity monitors—the device enables the intervention rather than being the intervention.

Target indoor relative humidity of roughly 40-60%

the viability of airborne respiratory viruses varies with ambient relative humidity


One of the few anti-aging interventions with randomized-trial proof: 24% less visible skin aging over 4.5 years, plus fewer melanomas at 10-year follow-up. Benefits require consistent daily use; evidence for preventing basal and squamous cell carcinoma is less certain. Mineral zinc oxide and titanium dioxide are the only UV filters the FDA currently classifies as generally recognized as safe and effective.

Daily broad-spectrum SPF 15 or higher, applied in adequate amounts

evidence supports beneficial effects of sunscreen on the occurrence of skin cancers and skin photoaging


Controlled studies consistently show improved skin hydration and elasticity with modest fine-line reduction; effects are surface-level and reversible, not structural rejuvenation. Oral HA has placebo-controlled support but the trials are small and mostly industry-funded. Not proven for longevity.

Studied topical creams use about 0.1% HA; oral HA trials used 120 mg/day for 8-12 weeks

application of hyaluronic acid to dry skin of elderly resulted in significant improvements in skin hydration


Meta-analyses show small, real gains in flexibility and less muscle soreness 24-48 h after hard exercise; effects on strength and performance are trivial, and it works no better than other warm-ups. 'Fascial release', detox and anti-aging claims have no human evidence.

Meta-analysis of 16 RCTs (n=515): foam rolling moderately reduces post-exercise muscle soreness at 24 h (SMD -0.53) and 48 h (SMD -0.77), with little immediate effect.

Journal of bodywork and movement therapies


Meta-analyses in older adults show real gains in leg strength, balance and function like sit-to-stand, but many trials are small and low quality. Bone-density benefits are small and site-limited — a 2025 analysis found benefit only at the total femur, not the spine or femoral neck. Weight-loss and 'lymphatic drainage' claims have no human trial support.

~20-50 Hz vibration frequency (typical range studied in trials)

effects of exercise on muscle strength and physical performance in older people with sarcopenia


No human trial has tested mineral drops directly — support is extrapolated from mineral-water research, where one RCT of calcium/magnesium-rich water reduced falls in older adults. Drops typically deliver small doses relative to dietary needs. A sensible way to restore what reverse-osmosis filtration strips out, not a proven longevity intervention.

Double-blind RCT (n=98, adults over 50): daily calcium/magnesium-rich mineral water cut falls by 82% at 6 months and improved appendicular muscle mass over 12 months — tested bottled mineral water, not drops.


Biometric Wearables (Sleep, HRV & Recovery)

Garmin's optical heart rate is among the better performers at rest and steady state and its GPS-derived pace and distance hold up, but no brand measures energy expenditure accurately, and a Garmin watch running the same submaximal-run algorithm underestimated laboratory gas-analysis VO2max by about 4.7 mL/kg/min, with the error roughly twice as large in the fittest runners. Sleep is the weak point: Garmin devices scored worse than research actigraphy on sleep/wake detection, and against polysomnography a Garmin multisport watch overestimated total sleep time by roughly 85 minutes and significantly misassigned sleep stages, overcalling light sleep and undercalling deep. Worth being blunt about: the Forerunner 265 does not have Garmin's FDA-cleared ECG app, which requires hardware only present on certain other models, so this watch has no rhythm-detection feature at all. The metric here with genuinely strong outcome evidence is steps, and that evidence is about steps rather than about any particular watch.

Use it for pace, distance and steps; pair a chest strap for interval and threshold work, because wrist optical heart rate lags at high intensity. Treat the VO2max estimate as a rough training marker and re-check it against an actual field test rather than reading it as a fitness score.

Umbrella review of 39 meta-analyses (163,992 participants): trackers add roughly 1,800 steps/day and 40 min/day of walking with about 1 kg weight loss — enough for the authors to recommend them.


One of the most studied supplements there is: dozens of randomized trials and meta-analyses show reliable gains in strength, power and lean muscle alongside resistance training, and it is well tolerated in healthy people. The strong evidence is for muscle and exercise performance; cognitive, bone and healthy-aging benefits are promising but less settled. It supports training — it is not a treatment.

3–5 g/day (creatine monohydrate); an optional ~20 g/day loading week works faster but isn’t required

Position stand: creatine monohydrate is the most effective ergogenic nutritional supplement for high-intensity exercise and lean mass, with an extensive safety record.

Journal of the International Society of Sports Nutrition


Controlled trials support short-term gains in flexibility and reduced soreness and stiffness, with emerging data in rehab populations. It does not improve — and may transiently reduce — strength or explosive performance when used right before activity. Studies are small, short, and mostly in young athletic adults, with no aging-outcome data.

Most trials use about 5 minutes of treatment per muscle group.

A systematic review of 11 trials (most with moderate risk of bias) found massage guns improve short-term flexibility and recovery but do not improve — and may transiently impair — strength, power, and agility.

Journal of functional morphology and kinesiology


Human trials most consistently show lower oxidative-stress markers and modestly better skin moisture and elasticity; metabolic, cognitive, and performance effects are weak and inconsistent. Trials are small and short, and no long-term clinical-endpoint data exist.

ASX significantly increased TAC; significant reduction in MDA, alleviating oxidative stress


For duration and cardiac metrics this is the best-validated device on this list: against an ECG reference across 536 nights the Gen 4 gave nocturnal resting heart rate within about 2% and HRV within about 6%, the best of five wearables tested, and against multi-night polysomnography the Gen 3 did not differ significantly from PSG for total sleep time, wake after sleep onset, light sleep or deep sleep. Sleep staging is still the soft spot everywhere, including here: per-stage sensitivity ran about 76-80% in a laboratory comparison, wake-detection specificity was 0.41 in a week of unrestricted home sleep, and the most favourable of those studies has an author who sits on Oura's medical advisory board. Readiness and Cardiovascular Age are proprietary composites with no published validation against any reference standard and no FDA clearance for any feature. Nobody has shown that acting on a Readiness score changes sleep, fitness or illness risk, and for a subset of people nightly scoring makes sleep worse rather than better - the pattern sleep physicians named orthosomnia.

Wear it nightly for at least two weeks before reading anything into a number; single nights are noise. The defensible outputs are sleep duration, nocturnal resting heart rate and the HRV trend. Readiness is a composite, not a measurement.

Previous studies have shown a positive correlation between heart rate variability and clinical outcomes, including all-cause mortality.


Meta-analyses support zinc lozenges shortening colds by about a third, but a 2024 Cochrane update rated the evidence low-certainty. Otherwise strong trial evidence exists only for the AREDS eye formulation; immune or longevity benefits in zinc-replete adults are weakly supported, and no trials show the picolinate form is superior.

Cold trials used lozenges providing >75 mg/day elemental zinc; chronic daily intake should stay at or below the 40 mg adult upper limit.

zinc was associated with a significant reduction in the duration of common cold symptoms


MK-7 reliably improves vitamin K-status markers, and one 3-year RCT found modestly better arterial stiffness in postmenopausal women; but the large hard-endpoint trials on aortic-valve calcification and bone density were negative. Mortality benefits are observational only.

180 µg/day MK-7 in the main 3-year arterial-stiffness trial.

vitamin K supplementation prevented progression of arterial stiffness compared with placebo


The most rigorous systematic review graded the evidence that continuous noise improves sleep as very low quality, and recent experiments found broadband noise can itself alter sleep architecture, with earplugs outperforming masking in one traffic-noise study. It may help in genuinely noisy settings — keep volume low (under ~50 dB) — but no study shows such a device improves long-term cardiovascular outcomes.

transportation noise increases the risk for cardiovascular morbidity and mortality


Silymarin consistently lowers liver enzymes and improves metabolic markers in NAFLD and showed a fibrosis signal in the best NASH trial, but that trial missed its primary endpoint and no study proves prevention of cirrhosis or liver-related death. Plain silymarin is poorly absorbed; phytosome formulations partly address this.

Silymarin exhibits antioxidant, lipid-lowering, antidiabetic, and hepatoprotective effects


Cohorts link habitual green tea drinking to lower mortality and RCTs show small real effects on weight (~1 kg), blood pressure, and lipids, but effects are often not clinically meaningful. High-dose concentrated extracts carry a documented, idiosyncratic liver-injury risk, so beverage-level intake has the best benefit/risk ratio.

Beverage-level intake (≥2 cups/day in cohorts); keep supplemental EGCG below ~800 mg/day, the regulatory safety threshold

reduce body weight, alleviate metabolic syndrome, and prevent diabetes and cardiovascular diseases


Small, short randomized trials and a 2024 meta-analysis show modest blood-pressure (~3–4 mmHg), lipid, and insulin-sensitivity improvements, but samples are small, durations short (4–12 weeks), extracts variably standardized, and no long-term outcome trials exist. An adjunct, not a substitute for antihypertensive therapy.

500 mg olive leaf extract showed a significant reduction in systolic BP


The strongest evidence is symptom relief in diabetic neuropathy plus modest glycemic, lipid, and inflammatory-marker improvements, mostly from small heterogeneous trials. The 4-year NATHAN 1 trial found no slowing of neuropathy progression, and European regulators flag a rare insulin autoimmune syndrome (autoimmune hypoglycemia) risk.

300–600 mg/day typical (600 mg/day optimal for neuropathy symptoms); up to 1,800 mg/day used in trials

In the 4-year NATHAN 1 trial, ALA improved neuropathy symptoms but did not significantly improve the primary neuropathy-impairment composite, leaving disease modification unproven.


Bright light is a first-line treatment for seasonal depression, and meta-analyses show it roughly doubles remission and response rates as an adjunct in nonseasonal depression; sleep benefits are smaller and the studies more heterogeneous. Effectiveness depends on correct use (morning timing, sufficient intensity), and it can rarely trigger hypomania in bipolar-susceptible people. The evidence is for mood and circadian sleep effects, not lifespan extension.

~10,000 lux white light for ~30 min each morning

bright light therapy can be regarded as an effective treatment for seasonal affective disorder


This is the most rigorously evaluated device on the list, and the regulatory picture is real: the ECG app, irregular rhythm notifications, AFib History, sleep apnea notifications and hypertension notifications are all FDA-cleared. Cleared means the feature performs as described, not that using it makes you healthier - in the Apple Heart Study only 0.52% of 419,297 people were ever notified, and among those who returned a usable ECG patch just 34% actually had atrial fibrillation, while a head-to-head against physician-read 12-lead ECG put the watch at 85% sensitivity and 75% specificity with 18% of tracings inconclusive. Sleep staging is far weaker than sleep duration: against polysomnography the watch underestimated deep sleep by 43 minutes and overestimated light sleep by 45. The USPSTF still finds the evidence insufficient to say that screening asymptomatic adults for atrial fibrillation improves outcomes, and among people already diagnosed with AF, wearable users had more testing, more procedures and more symptom preoccupation than matched non-users - which is the honest reason not to buy this to reassure yourself.

If the cardiac features are why you are buying it, turn on irregular rhythm notifications and AFib History and wear it overnight. A notification is a reason to see a clinician, not a diagnosis; the ECG app only tells you about the moment you held your finger on the crown.


The strongest signal is adjunctive therapy in chronic heart failure (the Q-SYMBIO trial plus a 33-trial meta-analysis), but a Cochrane review rates that evidence low certainty, and most large trials used ubiquinone rather than ubiquinol — ubiquinol's proven advantage is mainly absorption. Benefit is clearest where CoQ10 is depleted (statins, heart failure, high oxidative demand); it is not a proven lifespan intervention in healthy people.

100–400 mg/day (1,500 mg/day used in a multiple-system-atrophy trial)

In a multicentre double-blind phase 2 RCT (n=139), high-dose ubiquinol (1,500 mg/day) slowed functional decline in multiple system atrophy (UMSARS part 2 difference -1.7 vs placebo) and was well tolerated.


Grip strength is one of the most durable prognostic markers in epidemiology: in PURE across 17 countries and in half a million UK Biobank participants, lower grip tracked all-cause and cardiovascular mortality, and it did so after adjustment and across very different populations. This specific device also clears the bar that most consumer instruments fail - the Camry digital dynamometer has been tested head-to-head against the Jamar, the reference instrument, with excellent reliability and correlations of 0.97-0.99, so a cheap unit is genuinely measuring the thing. Two honest caveats - grip strength is a marker of overall muscle and health rather than a target in itself, and squeezing a dynamometer more often will not move it, since the intervention that moves it is resistance training, which is graded separately and is where the actual benefit lives. The second is that this is the site's second grip dynamometer: it measures exactly what the other one measures, the other is graded strong, and nothing in the evidence says a 200 kg-capacity unit tells a middle-aged adult anything a 90 kg one does not - buy one, and let price decide which.

Three squeezes per hand, seated, elbow at 90 degrees, best value recorded - and the same chair, same arm position, same time of day every time. Monthly is plenty. What matters is your own trend over years, not where you sit against a population chart.

lower handgrip strength associated with higher all-cause, cancer, and cardiovascular mortality risk


Lower grip strength is one of the most robust mortality risk markers in epidemiology — consistent across millions of participants and stronger than systolic blood pressure in the PURE cohort — but it is a marker, not a treatment: no trial shows that raising grip strength itself lowers mortality. Its value is tracking response to resistance training and flagging decline early; use a consistent protocol, because measurement technique materially changes readings.

Handgrip strength as a predictor of all-cause mortality


Several small, well-controlled randomized trials show improved muscle endurance and strength, lower inflammatory markers, and younger-looking immune-cell profiles, with an excellent safety record. But nearly all are short (4 months or less) and manufacturer-funded, some missed their primary endpoints, and there is no long-term disease or lifespan data. Most people cannot reliably make urolithin A from food — the rationale for direct supplementation.

1,000 mg/day in most trials (500–1,000 mg/day studied)

significant improvements in muscle strength with intake of Urolithin A


Randomized trials and meta-analyses support topical tranexamic acid for melasma, roughly comparable to hydroquinone with fewer side effects. Trials are short and heterogeneous, melasma often relapses after stopping, and benefits beyond pigmentation (general anti-aging claims) are extrapolation.

2-5% topical cream or serum, typically for 8-12 weeks

tranexamic acid is a new and promising drug for the treatment of melasma


Trials and an individual-patient meta-analysis show home monitoring lowers blood pressure only when paired with clinician-guided titration or similar support (about 3.5-6 mmHg systolic at 12 months); the device alone does little. Accuracy depends on buying an independently validated monitor and using the right cuff and technique, and most monitors sold online are unvalidated.

home blood pressure monitoring is an independent predictor of cardiovascular events


A few small, short, industry-funded randomized trials report cognitive and sleep benefits consistent with rodent mechanism data, but there is no independent replication and human brain-magnesium elevation has not been directly confirmed. It provides little elemental magnesium, so it is a cognitive-support candidate, not a way to correct magnesium deficiency.

1-2 g/day in trials (about 144 mg elemental magnesium per 2 g)

L-TAMS restoring global cognitive abilities of older adults; increased functional synapse density


Trials and meta-analyses show NMES or whole-body EMS can preserve or build muscle and strength in older adults and rehab patients, mainly as an adjunct to, not a replacement for, voluntary exercise. Effects on fat loss and pain are small or absent, evidence in healthy users is limited, and effortless-abs marketing claims are unsupported. Avoid with pacemakers or implanted defibrillators.

Across 13 randomized trials in adults over 60, whole-body EMS produced a large improvement in sarcopenia composite score versus controls (effect size 1.44).


Strong meta-analytic support for a small improvement in high-intensity exercise capacity (efforts of about 0.5-10 minutes); in older adults it raises muscle carnosine and may help exercise capacity, but strength, daily function, cognition and disease outcomes are unproven. Safety is clean apart from harmless transient tingling.

beta-alanine increased exercise capacity and eliminated endurance exercise induced declines in executive function


Randomized-trial meta-analyses show real short-term pain and function benefits in knee osteoarthritis, and clinical-grade devices aid fracture healing — but a review of whole-body wellness mats found the evidence insufficient, and a major insurer now judges the pain evidence inadequate. Sleep, energy and longevity claims are unproven. Avoid with a pacemaker/ICD or during pregnancy.

Beneficial effect of PEMF therapy on pain, stiffness, and physical function in osteoarthritis


Proven to slow progression of age-related macular degeneration in people who already have intermediate or late disease — it does not prevent AMD in healthy eyes, and cognitive benefits are unproven (null in AREDS2's older participants). Unlike the beta-carotene it replaced, it is safe for former smokers.

10 mg lutein + 2 mg zeaxanthin daily (the AREDS2 formulation)

improved cognitive performance (focus, episodic memory and learning, visuospatial working memory)


Meta-analyses show a small (~2–3 mmHg) blood-pressure reduction, mostly in people with hypertension; lipids and glucose show no meaningful effect, and oral bioavailability is poor. The headline 'senolytic' claims come from the dasatinib+quercetin drug combination in early trials — the biggest 2024 trial was negative overall — not from quercetin capsules alone.

≥500 mg/day (blood-pressure effects appear mainly at 500 mg/day and above)

quercetin supplementation significantly decreased systolic blood pressure


Effect sizes are small — about 2 mmHg for blood pressure and a modest improvement in insomnia scores — and benefits look greatest in people with low baseline magnesium intake. Most evidence comes from other salt forms (oxide, citrate), so glycinate-specific superiority claims outrun the data.

250–500 mg elemental magnesium/day (sleep trials used 250 mg as bisglycinate or 500 mg; BP analyses center near ~370 mg/day)

RCT (n=155): 250 mg elemental magnesium as bisglycinate improved insomnia severity versus placebo at 4 weeks (ISI −3.9 vs −2.3, p=0.049; small effect, d=0.2), with greater response in low-dietary-magnesium participants.


Decades of laboratory and animal data show wound-healing and collagen-stimulating effects, but rigorous human trials for skin aging are essentially absent — the best controlled study found no objective benefit, only higher patient satisfaction. Skin penetration is a known limitation that newer liposomal formulations are trying to solve.

Randomized split-face study (n=13): topical copper tripeptide after CO2 laser resurfacing gave no objective benefit over control for erythema, wrinkles, or skin quality, though patient-reported satisfaction was higher (p=0.04).


One of the few supplements tested in a 21,000-person outcomes trial: the primary cardiovascular composite narrowly missed significance, but cardiovascular death fell 27% and meta-analyses confirm small blood-pressure and endothelial-function benefits. Global cognition and type-2-diabetes prevention were null in large randomized trials.

500 mg cocoa flavanols/day (the COSMOS trial dose; vascular effects plateau near ~710 mg/day)

Cocoa flavanols have antioxidant and anti-inflammatory capacities and can improve vascular function


The CD38/NAD⁺ longevity mechanism is demonstrated in cells and mice, not people. Human efficacy data come from chamomile-extract trials delivering far less apigenin than capsules, showing modest anxiety relief, and free apigenin is poorly absorbed in human pharmacokinetic studies. No trial has tested isolated apigenin for sleep, NAD⁺, or aging outcomes.

CD38 inhibition by apigenin restored the intracellular NAD ratio and Sirt3 activity


Sleep benefits rest on small, partly industry-affiliated trials. The aging-hallmark improvements come from small, single-site trials of GlyNAC (glycine plus N-acetylcysteine), not glycine alone, and faded after supplementation stopped; independent replication is still needed.

glycine improves daytime sleepiness and fatigue induced by acute sleep restriction


Higher ventilation and lower CO2 reliably track with better cognition and sleep, and CO2 is the accepted real-time ventilation gauge. Whether CO2 itself, versus the pollutants it tracks, impairs thinking at typical indoor levels is still contested, and a monitor only helps if occupants act on its readings.

elevated indoor CO2 has been linked with impaired cognitive function


Meta-analyses support lower fasting insulin and HOMA-IR in PCOS and a possible reduction in gestational diabetes (low certainty). The review behind the 2023 international PCOS guideline calls the overall evidence limited and inconclusive, with metformin better on several outcomes. Aging or longevity outcomes are essentially unstudied in humans.

The insulin sensitivity improved in both treatment groups


A small set of RCTs and systematic reviews supports modest improvements in photoaging signs and pigmentation with consistent long-term use. Results depend heavily on formulation stability, and the benefits are cosmetic and dermatologic — not a systemic or longevity effect.

5–20% L-ascorbic acid, pH below 3.5, applied consistently for weeks to months

successfully improved stability, skin permeation and antioxidant protection against skin photodamage


Oral NMN reliably raises blood NAD⁺ and has been well tolerated in trials up to about 900–1,250 mg/day. Functional benefits so far are modest and population-specific (muscle insulin sensitivity in prediabetic women, aerobic capacity, walking speed, sleep quality), several meta-analyses are null for glucose, lipids and muscle mass, and no trial shows effects on aging, disease prevention, or lifespan.

Human RCTs used 250–1,200 mg/day orally; well-tolerated up to ~900 mg/day, with one dose-finding trial reporting benefits peaking near 600 mg/day. Most trials run 6–12 weeks.

Only trace amounts in food: edamame, broccoli and avocado supply roughly 0.25–1.9 mg per 100 g. You'd need dozens of pounds to match a single 250–600 mg dose, so diet can't reach studied levels.

In animal studies, β-nicotinamide mononucleotide (NMN) supplementation increases nicotinamide adenine dinucleotide (NAD) concentrations and improves healthspan and lifespan with great safety.


Fall prevention through balance plus strength exercise is among the highest-certainty findings in geriatric exercise science (Cochrane high-certainty; USPSTF Grade B recommendation). The evidence supports the training itself, not any specific device — benefit depends on regular, progressive use, and frail users should start supervised.

Balance-challenging exercise ~3+ hours/week; strength training ~30–60 min/week

balance training demonstrated better balance and functional mobility relative to control


Small, short RCTs and meta-analyses show modest glycemic improvements and a small delayed-recall benefit limited to specific memory domains. No long-term, aging, or lifespan outcomes have been tested, and several measured outcomes were null.

Meta-analysis of 23 randomized trials found histidine-dipeptide (carnosine/anserine) supplementation reduced waist circumference by about 3.5 cm and HbA1c by 0.76% versus control.

Obesity reviews : an official journal of the International Association for the Study of Obesity


Trials show small blood-pressure reductions and improved endothelial function and knee-osteoarthritis symptoms, but a Cochrane review rated nearly all pine-bark evidence very low certainty, and much of the positive literature comes from one manufacturer-funded group. No lifespan or hard-outcome data.

Pycnogenol augments endothelium-dependent vasodilation by increasing nitric oxide production


Meta-analyses show modest blood-pressure reductions (~2–6 mmHg systolic), largest in younger or metabolically impaired people; effects on lipids and glycemia are small and inconsistent. New fatty-liver benefits rest on two small single-country trials, one trial found no cognitive benefit, and no hard cardiovascular outcomes have been tested.

both supplementations significantly modulated blood pressure


Meta-analyses converge on small improvements in lipids and inflammatory markers, with reproducible short-term endothelial benefits; blood-pressure effects are inconsistent and one 2019 meta-analysis was entirely null. No trial has tested clinical event reduction.

~500 mg/day isolated, or via hesperidin-enriched juice

hesperidin protected individuals from postprandial endothelial dysfunction


Reliably lowers homocysteine (dose-dependent, meta-analyzed) and is FDA-approved for homocystinuria, but homocysteine reduction has never been shown to prevent cardiovascular events. At 4 g/day or more it modestly raises total cholesterol, and NASH and body-composition trials were null.

Across 5 RCTs at 4 g/day or more, betaine lowered plasma homocysteine by a pooled 1.23 µmol/L versus placebo.


Strong trial evidence supports this technology for preventing hospital blood clots and for venous and lymphatic disease, but that does not transfer to athletic recovery: a 2024 meta-analysis of 17 studies found only trivial-to-small benefits, clearest for reduced perceived soreness, with inconsistent effects on muscle-damage markers.

~20–30 min per session at ~80 mmHg in studies

intermittent pneumatic compression may provide short-term relief of delayed onset muscle soreness


Curated grade based on the human evidence for this specific product.

Salivary cortisol is a legitimate assay - late-night salivary cortisol is one of the recommended first-line tests for suspected Cushing syndrome, and its diagnostic accuracy has been characterised across 139 studies - but that is a specific endocrine question, asked by a clinician about a patient with reasons to suspect it, and it is not what this product is selling. Consumer 'stress testing' is a different claim, and there is no established evidence that a four-point daily cortisol curve in a well person measures psychological stress, predicts anything about their health, or identifies a treatable state such as 'adrenal fatigue', which is not a recognised diagnosis. The measurement is also unusually fragile in exactly the setting it is sold for: the day-curve depends on sample timing nobody is verifying, and the cortisol literature itself found that fewer than 6% of published studies electronically confirmed when samples were actually taken, with timing error producing frankly erroneous curves. Graded preliminary rather than as a measurement tool because the analyte is real but the consumer claim built on it has essentially no supporting outcome evidence - it is the weakest thing in this category and we would rather say so than file it alongside tests that work.

Across 147 studies, the cortisol awakening response correlated positively with job and general life stress and negatively with fatigue, burnout, and exhaustion.


Several small, short randomized trials (roughly 30–60 people, up to 12 weeks) report better memory, attention and cerebral oxygenation at about 20 mg/day, with good tolerability. But the trials are largely Japanese and manufacturer-linked, the mitochondrial-biogenesis mechanism is shown mainly in cells and animals, and there are no large independent trials or hard clinical endpoints. Promising early human evidence, not proven anti-aging efficacy.

PQQ is known to promote mitochondrial biogenesis and improved mitochondrial bioenergetics


The exposure it measures is unambiguous: long-term PM2.5 is one of the most replicated environmental causes of cardiovascular death, and consumer optical sensors are validated as reliable trend instruments. One trial showed monitoring with feedback cut indoor PM2.5 by a median of about 19%, but direct evidence that owning a monitor improves health outcomes is early, and the benefit depends on acting on the readings.

Providing households with PM2.5 monitoring plus feedback led 66% of 86 homes to reduce indoor PM2.5, by a median of 4.1 µg/m³ (−19%).


Two meta-analyses (2018 and 2026) converge on a real antidepressant effect comparable to standard drugs but with fewer side effects, plus small cognitive benefits in mild cognitive impairment and early Alzheimer's and less fatigue in the very old. Depression trials are highly heterogeneous and mostly older, and a Cochrane review found no cognitive benefit in healthy people. Not proven for general anti-aging.

Meta-analysis of 10 trials (809 participants) confirmed a significant antidepressant effect versus placebo, comparable to standard antidepressants with fewer adverse effects.


One small but well-designed split-face RCT (33 women, 12 weeks) showed a 5% alpha-lipoic acid cream reduced facial roughness more than vehicle (50.8% vs 40.7% by profilometry), and one formulation study found similar anti-wrinkle effects without irritation. There are no large or long-term trials, and most commercial creams are untested at the studied concentration. A plausible modest benefit for skin texture and fine lines — not a systemic anti-aging intervention.

a cream containing alpha-lipoic acid improves clinical characteristics related to photoageing


It reliably raises folate status and lowers homocysteine, and randomized trials plus a 2022 meta-analysis show a modest adjunctive benefit in SSRI-resistant depression at 15 mg/day with placebo-like tolerability, likely concentrated in inflammatory or metabolic subgroups. But homocysteine lowering has not translated into clear cardiovascular or cognitive outcome benefits, and longevity uses are extrapolations, not tested.

15 mg/day as antidepressant adjunct (7.5 mg was ineffective)

Adjunctive L-methylfolate modestly improved antidepressant response versus placebo (RR 1.25 for HAMD-17 response; SMD −0.38), supporting the 15 mg/day trial findings.


Nearly all senolytic evidence is preclinical, and the 2018 mouse lifespan finding was not replicated by the NIA Interventions Testing Program in 2024. Small human RCTs show anti-inflammatory effects (for example 100 mg/day for 7 weeks in cancer patients), but no published trial has shown senescent-cell clearance or aging benefits in healthy people. Anti-aging use remains speculative pending larger trials.

we discover pro-survival Senescent Cell Anti-apoptotic Pathways and the first senolytic agents


Human evidence is indication-specific and mostly for combination products, not standalone luteolin. PEA-luteolin improved post-COVID smell recovery in randomized trials, but luteolin alone was no better than placebo in a Gulf War Illness crossover trial. Oral bioavailability is poor and the mast-cell/neuroinflammation promise remains largely preclinical.

luteolin can suppress neuroinflammatory response, microglia activation, and oxidative stress


Human data are mostly observational: higher blood ergothioneine tracks with lower cardiovascular and all-cause mortality in large cohorts, but causality is unproven - it may partly mark a healthy, mushroom-rich diet. The one controlled cognition trial was positive but tiny (n=19). Appears safe at studied doses; larger randomized trials are needed.

25 mg three times weekly (the regimen in the 1-year cognition pilot RCT)

higher ergothioneine was an independent marker of lower risk of cardiometabolic disease and mortality


Strong dermatology evidence for rosacea, acne and melasma at prescription 15-20% strengths, built on decades of RCTs and GRADE-assessed reviews. Benefit at over-the-counter ~10% cosmetic doses is plausible but less directly proven. Mild, transient stinging is the most common side effect; a skin-health product, not a systemic longevity intervention.

15-20% topical gel/cream (prescription strengths used in most trials)

effective in the treatment of rosacea with decreases in inflammatory lesion count


One solid 12-week RCT found 0.5% bakuchiol comparable to 0.5% retinol for photoaging with less scaling and stinging, but the total evidence base is small, short and partly industry-funded. Bakuchiol is not a retinoid, and deep-wrinkle or long-term efficacy is unproven. Tolerability is its clearest advantage.

0.5% twice daily (the head-to-head RCT regimen)

bakuchiol is comparable with retinol in improving photoageing and is better tolerated


Large international cohorts and a 2025 patient-level meta-analysis consistently show 24-hour and nighttime ambulatory readings predict death and cardiovascular events better than office measurements, and US guidelines recommend confirming hypertension out-of-office. No randomized trial has shown that ABPM-guided treatment itself improves outcomes — the value is in better management, and one influential 2018 cohort study in this field was retracted in 2020. Consumer devices should be clinically validated with a properly fitted cuff.

In an 11,135-person international cohort with median 13.8-year follow-up, each 20 mmHg higher nighttime systolic pressure was associated with 23% higher all-cause mortality and 36% higher cardiovascular-event risk, independent of office readings.


Human trials and meta-analyses support small blood-pressure reductions (a few mmHg) and one year-long trial suggests memory preservation, but at least one systematic review calls the blood-pressure evidence weak. The headline mitophagy benefits were shown mainly with purified urolithin A, not pomegranate extract, and microbiome conversion of ellagitannins varies widely — many people are low producers.

In 261 adults aged 50–75, daily pomegranate juice for 12 months kept visual memory performance stable while the placebo group declined.

The American journal of clinical nutrition


Oral NMN reliably raises blood NAD⁺ and has been well tolerated in trials up to about 900–1,250 mg/day. Functional benefits so far are modest and population-specific (muscle insulin sensitivity in prediabetic women, aerobic capacity, walking speed, sleep quality), several meta-analyses are null for glucose, lipids and muscle mass, and no trial shows effects on aging, disease prevention, or lifespan.

In animal studies, β-nicotinamide mononucleotide (NMN) supplementation increases nicotinamide adenine dinucleotide (NAD) concentrations and improves healthspan and lifespan with great safety.


Randomized trials show real biomarker effects — enhanced carcinogen detoxification and a modest glucose-lowering signal in prediabetes — but these are surrogate markers, not proven disease-outcome reductions. Actual sulforaphane delivery varies widely between supplements unless active myrosinase is retained. Mild gastrointestinal upset is the main side effect.

sulforaphane activates Nrf2 and delays senescence by decreasing glucose metabolism and oxidative damage


Positive sleep trials are small (8–20 people), short, and mostly juice-based, and recent better-powered trials using common powder doses in non-insomnia populations were null. Best case is a mild, food-level sleep aid for older adults with insomnia; formulation, dose, and baseline sleep status clearly matter.

The 8 completers with insomnia increased sleep time by 84 minutes on polysomnography (P = 0.0182). Cherry juice procyanidin B-2 inhibited IDO, increased tryptophan availability, reduced inflammation, and may be partially responsible for improvement in insomnia.


The strongest human data are clinical — post-heart-attack secondary prevention, deficiency states, and frail centenarians — not healthy-longevity supplementation; weight effects are real but small (~1 kg). Chronic oral L-carnitine raises TMAO via gut bacteria, and whether moderate elevations are causal or merely risk markers remains unresolved — a legitimate caution for long-term daily use.

~2 g/day; analyses show no clear added benefit above ~3 g/day

L-carnitine is associated with a 27% reduction in all-cause mortality, a 65% reduction in ventricular arrhythmias, and a 40% reduction in anginal symptoms in patients experiencing acute myocardial infarction


GGT is a real risk marker, not a curiosity - pooled across 19 cohorts and more than 9 million people, those in the top third had roughly 1.6 times the all-cause mortality of the bottom third. It is also about as non-specific as a blood test gets - it rises with alcohol, with a long list of ordinary medications, with metabolic and fatty liver disease, and with obesity, and it does not tell you which of those it is - head-to-head work shows that direct markers such as phosphatidylethanol outperform indirect markers like GGT for identifying alcohol-related liver injury. That is the whole difficulty with buying it alone: a raised GGT gives you a question rather than an answer, and the next step is a full liver panel and a conversation with a clinician who knows what you drink and what you take. If you already know the answer to those questions, the test is unlikely to change what you do.

Not a tracking test. Reasonable once if you have a concrete reason - regular alcohol intake you want an objective read on, a medication known to affect the liver, or a metabolic picture you are already working on. Interpreting it in isolation is the mistake.

serum GGT may be useful for risk assessment of all-cause and disease-specific mortality


Several small RCTs (n = 23–40, 8–12 weeks) show objective, instrument-measured improvements in wrinkles, texture and pigmentation, with less irritation than prescription tretinoin — one cream matched a series of glycolic-acid peels. Trials are short, small and often industry-linked, and they measure appearance, not systemic aging.

Retinaldehyde is efficient and well tolerated for the improvement of the signs of photoaging


Meta-analyses of small RCTs show saffron beats placebo for mild-to-moderate depression and performs comparably to SSRIs with fewer side effects; sleep benefits are modest and some trials are null. Trials are short (4–12 weeks), often small and single-center, large independent replications are lacking, and it is not a replacement for prescribed treatment.

20–30 mg/day standardized extract (sleep studies used ~14–28 mg/day)

saffron extract could improve sleep duration and quality


HOMA-IR is a reasonable idea with a real problem underneath it. The formula itself has been in use since 1985 and correlates acceptably with clamp measures at a population level, but it is built on a fasting insulin value, and insulin has no reference measurement procedure - when 12 commercial assays from 9 manufacturers were compared against isotope-dilution mass spectrometry, differences ran from roughly -298 to +303 pmol/L and only one assay agreed fully with the reference, despite all of them claiming traceability to the same WHO standard. An earlier eight-assay comparison found median insulin concentrations differing by a factor of 1.8, which makes any published HOMA-IR cut-off essentially assay-specific: 2.4 from one lab and 2.4 from another are not the same finding, and a threshold you read online may not apply to your report at all. Note also that this product is a 7-in-1 metabolic panel rather than a dedicated insulin test - and if the question you are actually asking is whether your glucose metabolism is drifting, an HbA1c through a clinician is cheaper, standardised and interpretable.

Fasting 10-12 hours, and only ever compared against your own previous result from the same laboratory. Twice a year at most. Treat the trend as the signal and ignore the absolute HOMA-IR figure printed on the report.

insulin resistance is independently associated with greater risk of cardiovascular or all-cause mortality


hs-CRP has earned its place: it separated risk independently of LDL cholesterol in the classic NEJM prediction work, and in 30-year follow-up of the Women's Health Study it was still carrying predictive information decades after a single measurement. The measurement travels better than most on this list - CRP has been validated from finger-stick dried blood spots against automated analysers, with stability, haematocrit and precision formally checked, and remote self-collection in older adults has been shown to be reliable. The weakness is not the assay, it is the biology: CRP is an acute-phase protein that swings enormously with any infection or inflammation, so one number in isolation is close to meaningless and this product bundles it with vitamin D rather than selling it alone. Also worth saying plainly - a genuinely raised hs-CRP in a well person has no specific consumer fix attached to it; it is information you take to a clinician, not an instruction.

Only when you are well. Check it twice, a couple of weeks apart, and take the lower value - a single high reading is far more likely to be a cold than a signal. Do not test within 2-3 weeks of any infection, injury, vaccination or hard unaccustomed exercise.

elevated inflammatory index was significantly associated with cardiovascular disease incidence and mortality


Blood-pressure lowering is supported by sham-controlled RCTs and two 2023 meta-analyses, one with trial-sequential confirmation. But trials are small (about 25-100 participants), short (6-12 weeks), and many come from one research group; hard outcomes like stroke and heart attack are untested. An adjunct to, not a replacement for, exercise and prescribed antihypertensives.

30 breaths/day at ~75% of maximal inspiratory pressure, 5-7 days/week (~5 min/day)

Inspiratory muscle strength training lowers blood pressure and improves endothelial function


This is the one test on the list where the analyte and the method were developed together and both hold up. Pooled across 17 prospective cohorts, higher blood omega-3 levels tracked lower total and cause-specific mortality, the Framingham data point the same way, and the index adds predictive information on top of the pooled cohort equation - and unlike a serum fatty acid, red cell membrane composition is a stable several-month average rather than a snapshot of last night's dinner. Two things to hold in mind anyway - the evidence is observational, and people with a high Omega-3 Index differ from people with a low one in many ways, and the supplement trials designed to test whether raising it changes outcomes have come out mixed rather than clean, so a low number is a reason to eat more oily fish and not proof that a capsule will buy you the associated risk. And the index is a proprietary measure run by the laboratory whose founder developed it and co-authors much of the supporting literature - that is disclosed rather than hidden, but you should know it is not an independently standardised assay with an external reference method behind it.

Once to find your baseline, then again about 4 months after changing oily fish intake or starting a supplement - red cell fatty acids turn over slowly and anything sooner is reading noise. Most people sit around 4-5%; the level associated with lowest risk in the cohort work is roughly 8% or above.

a lower Omega-3 Index was associated with increased risk for total mortality and ischemic stroke


Ferritin is the standard first-line marker of iron stores and a genuinely low value is informative. The trap is that ferritin is also an acute-phase reactant, so it rises with infection, inflammation, obesity and liver disease - which means a normal or even high ferritin does not rule out iron deficiency in anyone with an inflammatory burden, and this is common enough to matter. The thresholds are shakier than they look, too: the WHO cut-offs of 12 and 15 micrograms per litre were set by expert opinion, and when NHANES data were used to derive thresholds anchored to actual iron-deficient erythropoiesis they came out substantially higher, so a result reported as normal against the old cut-off may not be. A ferritin on its own, without a CRP to interpret it against and without a full blood count, is a number you will end up taking to a clinician anyway - and iron is not a supplement to start on a home result, because taking it when you do not need it does harm.

Reasonable once if you have a specific reason - heavy periods, a plant-based diet, blood donation, unexplained fatigue - and again 3 months after starting iron, no sooner. Not a number to track routinely if you have no reason to suspect a problem.

serum ferritin levels between 200 and 1200 ng/ml associated with the lowest all-cause and cardiovascular death risks


Evidence is ingredient-by-ingredient: modest human RCT support for nattokinase (blood pressure), lutein/zeaxanthin (eye health), and inulin (glycemia), but rutin and trehalose rest mainly on preclinical data, and trehalose showed no efficacy in the large HEALEY ALS platform trial. No trial has tested the finished seven-ingredient product, gummy doses may fall below studied amounts, and no organ-function, healthspan, or lifespan benefit has been demonstrated.

A multi-ingredient blend, so there is no single human dose; effective amounts depend on each component and the specific formula. Check the individual ingredients and their label amounts.

Varies by formula. Many organ-support nutrients (choline, omega-3s, antioxidants, B vitamins) come from foods like fish, eggs, leafy greens and organ meats, but concentrated supplement amounts often exceed typical dietary intake.

Meta-analysis of 6 RCTs (n=546) found nattokinase reduced systolic blood pressure by about 3.5 mmHg and diastolic by 2.3 mmHg, with mixed lipid signals at low doses.


Human RCTs used 250–1,200 mg/day orally; well-tolerated up to ~900 mg/day, with one dose-finding trial reporting benefits peaking near 600 mg/day. Most trials run 6–12 weeks.


Strongest support is for osteoarthritis symptoms, with modest effects on inflammatory markers, lipids, and depressive symptoms; effect sizes are small and trials are short and heterogeneous in formulation. High-bioavailability products - especially piperine-boosted ones - have been linked to a growing case series of immune-mediated liver injury, so monitoring liver enzymes with prolonged use is prudent.

a reduction in C-reactive protein, interleukin-6 and tumor necrosis factor


Cystatin C genuinely outperforms creatinine alone. It is less dependent on muscle mass, the combined creatinine-cystatin C equation estimates GFR more accurately than either marker by itself, and where the two estimates disagree the cystatin C-based number is the one that tracks mortality and kidney outcomes - a large meta-analysis of that discordance makes the point clearly, and KDIGO now recommends cystatin C as a confirmatory test. That is exactly why it is a poor fit for a consumer kit: cystatin C earns its keep as a second, confirmatory measurement read alongside a creatinine, a urine albumin-to-creatinine ratio and your history, and an eGFR from a mailed sample with none of that context is a number without a denominator. It is also affected by things other than filtration - thyroid status, corticosteroids, body composition - so an abnormal result here leads directly to a clinician and a proper panel, which is a fair argument for starting there.

Not a routine self-monitoring test. Reasonable once if you have a specific reason to think a creatinine-based eGFR is misleading you - unusually high or low muscle mass, or a creatinine result you are trying to make sense of. Otherwise this belongs to whoever is already following your kidney function.

Patients with elevated cystatin C have a higher risk of all-cause, cardiovascular, and cancer death


Large cohorts link higher and more varied flavonoid intake to lower mortality, and a 281-trial meta-analysis found modest improvements in blood pressure, lipids, and glucose markers. But much of the evidence is observational (healthy-eater confounding), supplement trials use heterogeneous single compounds, and this exact blend has never been tested in a human trial—expect modest effects at most.

As a generic blend, dosing varies by formula; studied single polyphenols differ widely (e.g. resveratrol 150–500 mg/day, EGCG 300–800 mg/day). No single established dose applies to mixed blends.

Polyphenols are abundant in everyday foods: berries, dark chocolate/cocoa, green tea, coffee, red wine, olive oil, nuts and colorful produce can supply hundreds of milligrams to over a gram daily through a varied diet.

Across 281 RCTs (17,126 participants), polyphenol supplements modestly improved cardiometabolic markers—catechins lowered systolic blood pressure ~1.6 mmHg, anthocyanins improved lipids, curcumin improved glucose handling.


Meta-analyses of randomized trials show modest improvements in blood pressure, glucose, triglycerides, cardiac function, and endurance performance, with a good safety record. Anti-aging claims rest on animal lifespan data: no human trial shows slowed aging, and 2025 analyses found human taurine levels do not reliably decline with age.

Meta-analysis of 10 studies: oral taurine improved endurance exercise performance with a small-to-moderate effect.


The analyte is about as solid as anything on this site: LPA gene variants that raise Lp(a) track coronary disease in a dose-dependent way, the European Atherosclerosis Society treats a raised level as an independent causal risk factor, and in the 30-year follow-up of the Women's Health Study a single baseline Lp(a) still carried predictive weight three decades on. But this is not a standalone Lp(a) test - it is a multi-analyte heart panel that also returns ApoB and hs-CRP, so it overlaps two other tests on this list, and Lp(a) reporting still has a real standardisation problem: mg/dL and nmol/L are not interchangeable, and apo(a) isoform size biases mass-based assays. The part the marketing skips is that there is no licensed Lp(a)-lowering drug today - olpasiran and its class lower the number impressively, but the cardiovascular outcome trials have not reported. So a high result changes only how hard you and a clinician manage everything else you can actually move, which is worth knowing once, because the number itself will not change.

Once in adult life. Lp(a) is set by the LPA gene you were born with and moves very little afterwards, so one good result is the result. Repeat only if the units or the lab change and you cannot line the numbers up.

continuous, independent, and modest associations of Lp(a) concentration with risk of coronary heart disease and stroke


Water Purification (Reverse Osmosis & Ultrafiltration)

This filters on the same principle as reverse osmosis units costing several times more, and no trial has compared brands on any health outcome — which is the useful thing to know at this price. The removal chemistry is well documented; the health-outcome data are not, and the closest human evidence is observational, showing serum PFAS falling in communities after a contaminated water supply was replaced. If your utility's water quality report is compliant and PFAS are low, an RO system removes contaminants that were not measurably hurting you. RO also takes magnesium and calcium out along with everything else, and drinking-water magnesium is inversely associated with coronary mortality in observational studies — weak evidence, but it points one direction, so remineralize or cover it in your diet.

Same protocol as any RO system: find out what is in your water first, then decide. Replace pre-filters and the membrane on schedule, and either fit a remineralization stage or make sure magnesium and calcium are covered by your diet. Budget for filter replacements — that recurring cost, not the purchase price, is the real expense.

In controlled bench testing, point-of-use RO removed >95% of manganese and uranium and >98% of calcium, magnesium, iron, and copper, while activated carbon was generally ineffective for metals.


Blue-Light Management & Circadian Lighting

These have been tested properly and they did not work. That distinction matters: this is not thin evidence, it is adequate evidence pointing at nothing, which is why it is graded at the bottom rather than as something promising. The 2023 Cochrane review pooled 17 randomized trials and concluded that blue-light filtering lenses may make no difference to eye strain with computer use over short follow-up, probably make little or no difference to visual acuity, and have indeterminate effects on sleep — three trials reported improvement, three reported none. Cochrane also recorded the reported harms, infrequent but real, including headache, discomfort, lower mood and increased depressive symptoms; there is no evidence at all on macular health, contrast sensitivity or melatonin, because no trial measured them.

No protocol, because no wearing schedule has been shown to produce a benefit. If the goal is screen comfort, the treatable causes are dry eye, an uncorrected refractive error and not blinking — an eye exam is the better $38. If the goal is sleep, dim the lights and cut screen time in the hour before bed, which is where the evidence actually points.

Findings suggest that mistimed light exposure, including evening blue-enriched light, disrupts the human circadian rhythm and melatonin signalling.


Human data exist only for individual ingredients, not this product: GlyNAC improved oxidative stress and physical function in older adults at doses far above what the sachets provide (and includes NAC, which the formula lacks), glucosamine's mortality link is observational, and the fisetin and alpha-ketoglutarate anti-aging claims rest on animal data with human trials still underway. Pterostilbene raised LDL cholesterol by about 17 mg/dL in one randomized trial. The finished stack has never been tested in a human trial.

As an all-in-one blend, there is no single studied dose; each ingredient has its own evidence and the combination as a whole is rarely tested in humans. Review the per-ingredient label amounts.

Varies by formula. Some ingredients (vitamins, minerals, polyphenols) are common in foods, while others (NMN, CoQ10, specific botanical extracts) aren't meaningfully obtained from diet at supplemental levels.

Regular glucosamine use was associated with 15% lower all-cause mortality (HR 0.85) and 18% lower cardiovascular mortality among 495,077 UK Biobank participants — observational, so it cannot prove cause.


ApoB counts atherogenic particles rather than the cholesterol inside them, and where the two disagree the particle count is the better guide to risk - that part is well supported and is why several lipid guidelines now list it as a preferred target. Whether a mailed finger-stick delivers that number reliably is a separate question, and the honest answer is partly. A dried blood spot ApoB assay has been shown to correlate closely with a plasma reference method, but that work was done on laboratory-prepared spots from venous blood with a haematocrit correction applied, not on cards collected at a kitchen table and posted in July - collection technique, spot volume and haematocrit are all real sources of error nobody is controlling at your end. Treat a home ApoB as a screening number that tells you roughly which band you are in, and if it lands high, the next step is a venous panel through a clinician rather than a second kit.

Once to find out where you stand, then repeat about 8-12 weeks after any deliberate change - a statin, a real diet change, meaningful weight loss. Fasting is not required for ApoB. Stick to one lab, because between-lab differences are larger than the changes you are looking for.

In a meta-analysis of 233,455 people, apoB was the strongest lipid risk marker (relative-risk ratio 1.43 vs 1.34 for non-HDL-C and 1.25 for LDL-C), beating LDL-C by 12%.

Circulation. Cardiovascular quality and outcomes


Multiple meta-analyses show BFR at light loads builds muscle size comparably to heavy lifting, with somewhat smaller maximal-strength gains; in older adults it produced large strength gains and matched conventional training in one sarcopenia trial. Generally safe when supervised, but it raises exertion and discomfort, depends on correct cuff pressure, and needs medical clearance with clotting risk, uncontrolled hypertension, cardiovascular disease or pregnancy. Any longevity benefit is indirect, via preventing muscle loss.

Low loads of about 20-40% of one-repetition maximum with an individualized, limb-specific cuff pressure.

blood flow restriction resistance training is a valid and effective approach for increasing muscle strength


Oral NMN reliably raises blood NAD⁺ and has been well tolerated in trials up to about 900–1,250 mg/day. Functional benefits so far are modest and population-specific (muscle insulin sensitivity in prediabetic women, aerobic capacity, walking speed, sleep quality), several meta-analyses are null for glucose, lipids and muscle mass, and no trial shows effects on aging, disease prevention, or lifespan.

In animal studies, β-nicotinamide mononucleotide (NMN) supplementation increases nicotinamide adenine dinucleotide (NAD) concentrations and improves healthspan and lifespan with great safety.


Meta-analyses of randomized trials show small improvements in endothelial function and C-reactive protein, and one 24-month trial found cognitive and cerebrovascular benefits in postmenopausal women — from a single research group, awaiting replication. No trial shows effects on cardiovascular events, dementia or lifespan, the sirtuin longevity mechanism remains preclinical, and liposomal superiority over plain resveratrol is unproven in humans.

Human trials span ~150 mg/day to 2 g/day; ~500 mg/day raised SIRT1 activity. Evidence suggests a U-shaped curve, with ~1 g/day worsening some lipid markers — more is not better.

Red wine carries only ~0.2–5.8 mg per liter, so a 5-oz glass gives roughly 0.05–1.5 mg; grape skins and peanuts add trace amounts. Reaching a 150–500 mg trial dose from food alone is impractical.

Over 24 months, 75 mg twice-daily resveratrol improved overall cognitive performance by 33% versus placebo and enhanced cerebral blood flow and insulin sensitivity in postmenopausal women — a single-cohort result awaiting replication.

Clinical nutrition (Edinburgh, Scotland)


The preclinical case is unusually strong and several large prospective cohorts link higher dietary spermidine intake to lower mortality — but that is observational and confounded by diet quality. The most rigorous human trial to date (12-month SmartAge) found no cognitive or biomarker benefit at the 0.9 mg/day dose used in supplements, and oral bioavailability is unsettled.

Cognition trials in older adults used modest, food-level doses of wheat-germ extract: 0.9 mg/day for 12 months (SmartAge) and 1.2 mg/day for 3 months. Higher doses are less studied.

Readily obtained from food: wheat germ holds ~24–35 mg per 100 g (about 2–2.5 mg per tablespoon); natto, aged cheese, mushrooms and soy are rich too. A normal diet supplies ~10–15 mg/day, exceeding the doses tested.

Administration of spermidine, a natural polyamine, markedly extended the lifespan of yeast, flies and worms, and human immune cells, by triggering autophagy.


Meta-analyses of dozens of RCTs show metformin-like reductions in fasting glucose and HbA1c (~0.6–0.9%), but the trial base is small, short and mostly Chinese, with no large rigorous confirmatory trials and no hard-outcome data. Weight-loss effects are weak despite 'nature's Ozempic' hype. GI upset is common and berberine inhibits CYP3A4/2D6, so drug interactions are a real concern — not a substitute for prescribed medication.

Human trials typically use berberine HCl 500 mg two to three times daily (about 1,000–1,500 mg/day) for 8–24 weeks, lowering blood glucose and lipids comparably to metformin in some studies.

Not meaningfully obtained from food: berberine comes from medicinal plants (barberry, goldenseal, Oregon grape root) used as extracts; edible barberry berries contain only traces, so matching a 500 mg dose from food is impractical.

Across 37 RCTs (n=3,048) in type 2 diabetes, berberine lowered fasting glucose by about 0.82 mmol/L and HbA1c by about 0.63% without increasing hypoglycemia — though the underlying trials were mostly small and of variable quality.


Strong for correcting deficiency and bone health. In vitamin-D-replete adults the biggest RCTs (VITAL, DO-HEALTH) were null for cancer, cardiovascular events, fractures and mortality. Lower cancer mortality with daily dosing, fewer autoimmune diseases and preserved telomeres are secondary signals that need replication — benefit is clearest in people with low baseline levels.

The RDA is 600 IU/day (ages 1–70) and 800 IU/day (over 70); the large VITAL trial used 2,000 IU/day, and the tolerable upper limit for adults is 4,000 IU/day.

Few foods are naturally rich: wild salmon provides roughly 570–900 IU per 3–3.5 oz, while fortified milk has only ~100 IU per cup, so diet alone often falls short of higher studied doses, especially with limited sun exposure.

Vitamin D supplementation was associated with a reduction in cancer mortality but not all-cause or cardiovascular mortality in this meta-analysis of randomised controlled trials.


Oral glutathione genuinely raises body stores and lowers oxidative-stress markers in randomized trials (about 30–35% at 1,000 mg/day over 6 months), with early immune-marker signals. Clinical outcomes are thin: skin-lightening effects are modest and inconsistent, and no trial shows disease or longevity benefit. Precursor (GlyNAC) results are promising but come from small single-center trials.

Liposomal glutathione trials used 500–1,000 mg/day (Sinha 2018) and 300 mg in a 2026 crossover; by contrast, plain oral glutathione up to 3,000 mg barely raised blood levels (Witschi 1992) because gut enzymes degrade it.

Small amounts occur in fresh produce, raw meat and fish, but dietary glutathione is largely broken down by gut peptidases before absorption, so food isn't a reliable way to raise body glutathione versus precursor or liposomal approaches.

GlyNAC supplementation in older adults improved glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, and multiple hallmarks of aging.


The randomized evidence supports particle filtration, not this particular machine. Pooled across 17 sham-controlled trials, portable air cleaners lowered systolic blood pressure by about 2.3 mmHg, and a 2025 crossover trial in 154 adults living near highways found a 3.0 mmHg systolic benefit that appeared only in people already at 120 mmHg or above, with nothing in those with normal pressure. In the Detroit trial that matters most for the price question, a low-efficiency HEPA-type filter lowered blood pressure about as much as a true-HEPA unit, and reviewers graded the overall certainty of this literature very low. No trial has isolated the deep carbon bed — the part you are paying extra for — against any health outcome, so buy this for odours, solvents or wildfire smoke if you have those problems, not for the number on your blood pressure cuff.

Run it continuously in the room you actually sleep in, sized to that room. A purifier only cleans the air in the space it occupies, so one unit does not treat a house. Keep windows shut when outdoor air is bad, and replace the particle filter on schedule — a saturated carbon bed stops adsorbing and can release what it captured.

Long-term exposure to ambient air pollution was associated with the onset and progression of cardiometabolic multimorbidity in this prospective UK Biobank study.


Reverse osmosis removes what it claims to remove; the open question is whether your water contains anything worth removing. Pull your utility's water quality report first — if it is compliant and PFAS are low, this unit is stripping contaminants that were not measurably harming you, and what you are buying is reassurance. Where RO earns its place is genuine contamination, and even there the human evidence is indirect: when New Jersey communities had a PFAS-contaminated supply replaced, serum PFNA fell about 27% over two years, but nobody has randomized households to under-sink RO and followed a health outcome. A review of point-of-use devices found only five studies measuring real-world removal at the tap, short-chain PFAS are the hardest to catch, and RO strips magnesium and calcium along with the rest.

Test before you buy: a certified lab test, or your utility's annual consumer confidence report, tells you whether you need this at all. If you install it, replace membranes and pre-filters on schedule — an exhausted carbon pre-filter can release what it previously captured. Add a remineralization stage, or make sure your diet reliably covers magnesium and calcium.


WHOOP is good at the thing it does not advertise and weaker at the thing it does. Against polysomnography it got total sleep time almost exactly right - an 8-minute non-significant overestimate, and in a later systematic review the smallest total-sleep-time disagreement of the devices compared - but its specificity for detecting wake was only 51%, four-stage agreement was 64% with a kappa of 0.47, and the same review found it had the largest REM disagreement of the group at 21 minutes. Be precise about the regulatory picture: the FDA-cleared ECG feature sits on the more expensive WHOOP MG, not on the 5.0, and Blood Pressure Insights has never been FDA-cleared - the FDA issued a warning letter over it in July 2025 and closed that letter in June 2026 after WHOOP changed the display, leaving the feature as an unregulated wellness output rather than a validated blood pressure measurement. Strain and Recovery are proprietary composites with no external validation; HRV-guided training has modest meta-analytic support as a training principle in endurance athletes, but that is not evidence for WHOOP's particular score, and this is the only device on the list that also requires an ongoing subscription.

Wear it continuously and read Recovery as a rolling trend across weeks. If you are going to act on HRV, act on the direction of a multi-week average, not on a single morning's score.

WHOOP agreed with polysomnography on 89% of epochs for sleep vs. wake (95% sleep sensitivity) and overestimated total sleep time by only about 8 minutes.


This is the same measurement platform as the more expensive Garmins with fewer running features, and it inherits the same profile: steps are accurate enough to act on, heart rate is good at rest and steady state and degrades with wrist motion, and energy expenditure is not accurate in any consumer device from any brand. Sleep is where it is weakest - a systematic review of a comparable Garmin against polysomnography found only moderate accuracy for sleep stages and total sleep time, and in a laboratory comparison Garmin devices detected wake worse than research-grade actigraphy did. Like the Forerunner 265, the Vivoactive 6 does not carry Garmin's FDA-cleared ECG app, so there is no rhythm-detection function here regardless of what the heart-rate alerts feel like. The one number on this watch with strong outcome evidence behind it is the step count, where mortality falls steeply between about 2,000 and 7,000 steps a day - and a $90 tracker counts those steps about as well.

Use it for steps, pace and everyday heart rate; add a chest strap if you train by heart-rate zones. Read the sleep score as a duration estimate and ignore the stage breakdown.

Previous studies have shown a positive correlation between heart rate variability and clinical outcomes, including all-cause mortality.


This is the honest value on the list, and the reason is unflattering to everything above it: for the single output with strong outcome evidence behind it - the step count - a cheap tracker performs about as well as a watch costing eight times more. The step evidence itself is genuinely strong: pooled across 15 cohorts and 47,471 adults, all-cause mortality fell progressively with steps per day up to about 6,000-8,000 in people over 60 and 8,000-10,000 in people under 60, and a 2025 dose-response meta-analysis put 7,000 steps a day at 47% lower all-cause mortality than 2,000. What the device does less well is everything else: energy expenditure is inaccurate, sleep duration is decent but staging is mediocre, and the irregular rhythm notifications run Fitbit's FDA-cleared photoplethysmography algorithm but there is no ECG app on this model to capture a tracing when one fires. And a tracker is not a substitute for the behaviour - in the IDEA trial, adding a wearable to a supervised weight-loss programme produced less weight loss at 24 months than the programme alone, 3.5 kg versus 5.9 kg.

Wear it every day and use one number: steps. Aim for a personal increase of 1,000-2,000 steps a day over where you currently are, rather than for 10,000, and ignore the calorie estimate entirely.


Two features here are genuinely FDA-cleared: the ECG app, cleared in 2020, and the photoplethysmography-based irregular rhythm notifications, cleared in 2022. The Fitbit Heart Study is the honest reading of the second - of 455,699 participants only 1% ever received a detection, and among those who wore a confirmatory ECG patch, 32% had atrial fibrillation on it; separately, head-to-head against a physician-read 12-lead ECG the Sense's ECG app was 66% sensitive and 79% specific with 21% of tracings inconclusive, the weakest of the smartwatches in that comparison. Sleep duration is reasonable and staging is not: against polysomnography the Sense 2 overestimated light sleep by 18 minutes and underestimated deep sleep by 15, and the EDA-based stress score has no reference standard to be validated against at all. The USPSTF finds the evidence insufficient to say that screening asymptomatic adults for atrial fibrillation improves outcomes, and people who already have AF and wear these devices end up with more testing and more preoccupation, not demonstrably better health.

Leave irregular rhythm notifications on and wear it overnight for the sleep and resting heart rate trend. If you get a notification, use the ECG app to capture a tracing at the time, and take that to a clinician - it is a prompt to be checked, not an answer.


Polar's step counts and sleep duration track research instruments closely enough to be useful, but the systematic review of wrist-worn Polar devices concluded their accuracy remains unclear because the individual studies conflict, and energy-expenditure error is large in all of them. Against polysomnography in sleep-clinic patients a Polar multisport watch overestimated total sleep time by about 45 minutes, overestimated light sleep, underestimated deep sleep, and failed to detect daytime sleep at all; against an ECG reference across 536 nights, Polar had the poorest nocturnal HRV agreement of five wearables tested, with a mean absolute percentage error of 16%. The wrist ECG on the Vantage V3 exists to run Polar's orthostatic and recovery tests and carries no FDA clearance to detect an irregular rhythm, so unlike an Apple Watch, a Fitbit or a Withings device this watch is not a rhythm check. Trackers as a class do get people moving, roughly 1,800 extra steps a day in pooled trials, but that effect belongs to any step counter, and nothing in the literature says the extra several hundred dollars over a basic tracker buys a different outcome.

Wear it daily and treat the step count as the one output with real outcome evidence behind it. Read sleep stages, Nightly Recharge and training-load numbers as week-to-week trends rather than nightly verdicts, and confirm any heart-rate-driven training decision with a chest strap.


Two questions matter for a CGM worn without diabetes, and both answers are uncomfortable. On accuracy: in healthy adolescents the Libre's mean absolute relative difference against fingerstick plasma glucose was 13.1%, with only 68% of paired readings meeting the ISO 15197:2013 criterion, and in children without diabetes it showed magnitude bias at fasting levels and correlated poorly with true fasting glucose (r-squared 0.06) — it is built to track the large swings of diabetes, not to resolve the narrow band a normoglycemic person lives in. On whether measuring changes anything: the meta-analysis of 25 randomized trials of CGM as a behaviour-change tool found a modest HbA1c benefit driven by participants who had diabetes, no significant effect on weight or BMI, and only three trials in people without diabetes. Healthy people already spend roughly 15% of the time in the prediabetic range on CGM, and when 18 expert clinicians were handed non-diabetic CGM reports they could not agree on who needed follow-up — so expect to see spikes, and expect that nobody can currently tell you what they mean.

Treat it as a two-week experiment, not a permanent feed. Test specific questions — how your usual breakfast compares with a higher-protein version, what a 15-minute post-meal walk does to the curve — then take the sensor off. Do not chase a flat line: post-meal rises are normal physiology, and there is no validated target range for people without diabetes.

Continuous glucose monitoring use has several potential positive effects on management, including increased time in range and optimized therapy.

International Journal of Environmental Research and Public Health


The FDA clearance on this scale is narrow and specific: it covers detection of atrial fibrillation from the 6-lead ECG, and nothing else. The bioimpedance body composition is the part most people buy it for, and it is the part that does not hold up at an individual level: against DXA, bioimpedance underestimates body-fat percentage by roughly 5 to 6 percentage points and overestimates fat-free mass by around 4 kg, with limits of agreement wide enough that published comparisons conclude the two methods are not interchangeable for one person, only for group averages. I could not find any published validation of the vascular-age or nerve-health scores against a reference standard. Self-weighing does genuinely help, adding about 1.7 kg of weight loss when built into a behavioural programme, but that benefit comes from stepping on a scale regularly and works on a $25 one; no trial shows that watching your body-fat percentage or vascular age changes any outcome.

Weigh at the same time each morning, after voiding and before eating, and read the trend line over weeks rather than any single day. Use the weight; treat the body-fat, segmental and vascular readings as rough estimates that drift with hydration.

In this 91-person RCT, daily smart-scale weighing with email feedback produced −6.55% body weight at 6 months versus −0.35% in controls (42.6% vs 6.8% achieved ≥5% loss).


There is no peer-reviewed validation of this device — not a small study, not a flawed one, none. It launched at CES in January 2026, has no PubMed record, and publishes no sensitivity, specificity or limit of detection, so nothing here is graded on its own data. What can be graded is the category, and that history is not reassuring: the Nima sensor, the most-studied consumer allergen detector, missed 10% of samples at or above the 20 ppm gluten threshold, was unreliable below 10 ppm in most food matrices, and returned false positives in cream cheese and yogurt depending on how much sample was loaded. If your allergy is anaphylactic, price the cost of a false negative honestly — the AOAC stakeholder guidance states that consumer devices should not be used in isolation to decide whether a food is safe to eat.

There is no validated protocol for this device. If you use one at all, use it as an extra check on top of asking the kitchen, reading labels and carrying your epinephrine auto-injector — never as the thing that decides whether you eat. One tested crumb does not represent a plate, because allergens are usually distributed unevenly through a dish.

In this randomized pilot, celiac patients rated a portable gluten sensor an acceptable aid to gluten-free-diet adherence and quality of life, while citing cost, capsule supply, and false-result anxiety as barriers.

Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association


Decades of trials are genuinely mixed: one 3-year RCT showed slowed knee joint-space narrowing, but the NIH GAIT trial and a 2018 JAMA meta-analysis found little to no pain benefit over placebo. The UK Biobank mortality association (HR ~0.85) is observational and has drawn published selection/healthy-user-bias critiques—longevity benefit is unproven. Generally safe and inexpensive; caution with warfarin, shellfish allergy, and blood glucose.

Pivotal osteoarthritis trials used 1,500 mg/day of glucosamine sulfate, given once daily in the structure-modifying trials (Reginster 2001; Pavelka 2002); the GAIT trial used glucosamine hydrochloride 500 mg three times daily.

There is essentially no dietary glucosamine: it is extracted from crab, shrimp and lobster shells (chitin), which people don't eat, so reaching the studied 1,500 mg/day from food is not realistic.

Regular glucosamine use was associated with significantly lower all-cause, cardiovascular, cancer, respiratory and digestive mortality (all-cause HR 0.73).


Small human trials show GlyNAC restores glutathione and improves oxidative-stress, mitochondrial and physical-function markers, but nearly all come from one research group, the largest placebo-controlled trial enrolled 24 older adults for 16 weeks, and benefits faded after stopping. The ~24% lifespan extension was shown only in mice; there are no human data on disease or mortality outcomes.

In the Baylor/Sekhar trials, older adults took glycine 1.33 mmol/kg and N-acetylcysteine 0.83 mmol/kg daily (~100 mg/kg of each, roughly 7 g + 7 g for a 70 kg adult) for 16 weeks.

Glutathione itself isn't absorbed intact from food; the body builds it from precursors. Glycine is plentiful in collagen, meat and gelatin, but NAC is synthetic and not a food component, so trial-level intake is hard to reach by diet alone.

GlyNAC supplementation improved glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, physical function and multiple hallmarks of aging in older adults.


Evidence is indication-specific: moderate-certainty Cochrane support for preventing antibiotic-associated and C. difficile diarrhea and for reducing respiratory infections, but IBS and general wellness benefits are low-certainty and strain-specific. Multi-strain, high-CFU blends are not proven better than single strains, and commercial formulas rarely match the studied ones. Generally safe in healthy people; rare invasive infections have occurred in vulnerable hosts.

Human trials commonly use about 1–50 billion CFU/day (often 10^9–10^10), with many multi-strain products at 10–25 billion CFU; some high-potency formulas reach 100+ billion.

Fermented foods supply live cultures: kefir roughly 10–30 billion CFU per cup and yogurt about 1–10 billion per serving, so a daily serving can match lower-dose supplements but with fewer, undefined strains.

In older adults, multi-strain probiotic supplementation raised the anti-inflammatory cytokine IL-10 and short-chain fatty acids, although hs-CRP did not differ from placebo.


A flagship pilot RCT and 2025-2026 follow-up trials show real but modest benefits on insulin sensitivity, weight and HbA1c, but the trial base is small, a 2026 multicenter trial missed its primary endpoint, and benefits may appear mainly in people with low baseline Akkermansia. No long-term safety or hard-outcome data yet.

The key trial (Depommier 2019) gave 10^10 (10 billion) cells/day of pasteurized A. muciniphila for 3 months, improving insulin sensitivity and cholesterol in overweight adults.

Not obtainable from food: Akkermansia is a native gut microbe, not present in any food or normal probiotic; diet can only feed existing colonies via fiber and polyphenols (chicory inulin, cranberry, grapes).

Akkermansia muciniphila supplementation was safe and well tolerated and improved insulin sensitivity and markers of metabolic health in overweight, insulin-resistant adults.


One of the best-studied prebiotic fibers: reliable for constipation relief, with small (~1 kg) average weight effects and small LDL/triglyceride reductions whose certainty is rated low to very low. Commonly causes gas and bloating at higher doses; not a proven longevity intervention.

Human trials show prebiotic and metabolic effects at roughly 4–16 g/day, with many gut and cardiometabolic studies using about 10 g/day; higher doses often cause gas and bloating.

Readily food-derived: chicory root is richest (~35–45 g per 100 g, but eaten in tiny amounts), while raw garlic (~9–16 g/100g), Jerusalem artichoke (~16–18 g/100g), onion, leeks and asparagus can supply several grams daily.

Inulin increased gut Bifidobacteria and improved HOMA-IR after adjustment, though it did not significantly improve peripheral insulin sensitivity in this pilot trial.


Concordant meta-analyses and a pivotal RCT in hypertensives show roughly 5-8 mmHg systolic BP reductions and improved vascular function, plus modest exercise-performance gains. Most trials are small and short, diastolic effects are inconsistent, individual responses vary, and long-term outcomes (stroke, heart attack) are untested. Antiseptic mouthwash blocks the effect by killing the oral bacteria that activate nitrate.

Trials use ~70–250 mL beetroot juice or concentrate delivering roughly 4–13 mmol (about 250–800 mg) nitrate per day; a typical beet shot provides ~6.4 mmol (~400 mg).

Fully food-based: one cup of cooked beets, or ~100 g of arugula (~480 mg nitrate) or raw spinach (~250 mg), provides nitrate in the same range as the studied juice doses.

Pivotal RCT in hypertensive patients (n=68, 4 weeks): daily nitrate-rich beetroot juice lowered clinic BP by 7.7/2.4 mmHg and 24-h ambulatory BP by 7.7/5.2 mmHg, improved endothelial function ~20%, with no tachyphylaxis.


Meta-analyses of randomized trials consistently find PEA reduces chronic pain with few side effects, but the underlying trials are small, heterogeneous and often industry-linked, so the large pooled effect sizes may shrink in bigger independent studies. Evidence supports adjunctive pain relief, not anti-aging effects.

PEA was associated with significantly greater pain reduction compared to inactive control conditions (P < 0.001)… PEA may be a useful treatment for pain and is generally well tolerated.


Trials and meta-analyses show reduced osteoarthritis pain and stiffness, but results are inconsistent - one meta-analysis found no significant overall effect once trial heterogeneity was accounted for. Many trials are small or industry-sponsored, and key boswellic acids are poorly absorbed, so the formulation matters.

Of 20 supplements investigated in 69 studies, seven demonstrated large and clinically important effects for [osteoarthritis] pain reduction at short term.


Small randomized trials show statistically significant but clinically mild improvements in knee pain and function over 8-12 weeks, with some null results. There is no evidence of disease modification or anti-aging benefit, and effects look smaller and slower than NSAIDs. Safety is excellent (GRAS) at typical doses.

Compared to placebo, MSM produced significant decreases in WOMAC pain and physical function impairment (P<0.05).


Evidence for the mat itself is very thin: the only controlled trial found daily mat use reduced subjective stress no more than simply lying down and relaxing, with no change in blood pressure, heart rate or pain thresholds. Better evidence exists for targeted acupoint acupressure (sleep, some pain), but it may not transfer to blunt whole-back mats. A low-risk relaxation aid, not a proven pain or longevity intervention.

Pain was reduced by 35–36% in the acupressure groups compared with usual care… acupressure demonstrated promising support of efficacy for pain and fatigue reduction.


Human evidence at supplement doses is limited to brain-imaging pharmacokinetics, observational data and one small open trial; no randomized trial has tested 5 mg lithium orotate for cognition, mood or aging. The headline 2025 Nature findings came from mouse experiments, and experts caution against self-treatment pending human trials. Lithium has a narrow therapeutic index at drug doses, so treat long-term low-dose safety data as incomplete.

5 mg elemental lithium per capsule (about 1/25th-1/40th of a psychiatric dose)

We find an inverse correlation between drinking water lithium concentrations and all-cause mortality in 18 neighbouring Japanese municipalities (1,206,174 individuals)... a comparably low concentration of lithium extends lifespan of C. elegans.


Voltaren Arthritis Pain Gel (Diclofenac 1%)

The best-evidenced OTC pain topical — Cochrane and meta-analysis support for hand and knee osteoarthritis, with low systemic absorption. Relief is symptomatic and modest (about 1 in 10 extra users gets at least halved pain over 6–12 weeks), and it is still an NSAID: don’t combine with oral NSAIDs without advice, and avoid with NSAID allergy or in late pregnancy.

1% gel (~2–4 g) over the joint up to 4×/day; relief builds over ~7 days

In studies lasting 6 to 12 weeks, topical diclofenac and topical ketoprofen were significantly more effective than carrier for reducing pain; about 60% of participants had much reduced pain.


Capzasin-HP Capsaicin 0.1% Pain Relief Cream (Pack of 3)

A burning sensation on application is expected (about 1 extra case per 3 users in trials) and fades with regular use. Evidence is strongest for the prescription 8% patch in nerve pain; OTC creams give modest osteoarthritis relief, and a 2024 meta-analysis rates the certainty as low. Wash hands; keep away from eyes and broken skin.

0.025–0.1% cream 3–4×/day for at least 1–2 weeks (the 8% patch is prescription-only)

Meta-analysis of 8 RCTs (n=498) found topical capsaicin superior to placebo for osteoarthritis pain (SMD −0.84) but rated certainty low to very low, with application-site burning common (number-needed-to-harm 3).


Aspercreme 4% Lidocaine Pain Relief Cream

Best for small, well-localised pain — the strongest evidence is the 5% patch for shingles nerve pain, though one trial found an OTC-strength patch comparable. Cochrane notes high-quality RCTs are limited, and relief is purely symptomatic. Don’t exceed the labelled area or frequency, and avoid unregulated high-strength numbing products sold online.

4% OTC cream/patch to a small area up to 3–4×/day (the 5% patch is prescription)

Double-blind RCT (n=87): an over-the-counter-strength lidocaine patch was non-inferior to the prescription 5% patch and superior to placebo for back pain and arthritis.


Topical Menthol (Cooling Counterirritant)

Relief is mainly immediate cooling comfort, not disease-modifying; trials are small and short, mostly in acute muscle soreness. Menthol gel beat ice in one soreness trial and helped in a migraine study, but evidence for chronic joint pain is thin. NSAID-free and low-risk.

Apply gel to the area up to 3–4×/day as needed

Both ibuprofen/levomenthol and diclofenac gels provided superior global pain relief compared with ibuprofen gel, with a shorter median time to significant pain relief. Only ibuprofen/levomenthol gel provided cooling for up to 2 hours.


Salonpas Pain Relieving Patch (Methyl Salicylate + Menthol)

Topical Methyl Salicylate + Menthol (Medicated Patch)

Moderate evidence for short-term relief of acute muscle strain and sprains — one solid placebo-controlled patch trial plus Cochrane support — but chronic-pain data are lacking and relief is symptomatic only. Rare but real risks: skin irritation and chemical burns with occlusion or heat, and case reports of warfarin potentiation through skin absorption.

1 patch (methyl salicylate ~10% + menthol ~3%) over the painful area, up to 8 hours per application

Findings suggest topical NSAIDs may be effective and well tolerated for managing acute musculoskeletal pain; interventions included ketoprofen gel, methyl salicylate/1-menthol patch, and diclofenac epolamine patch.


Osteo Bi-Flex Triple Strength (Glucosamine Chondroitin + Joint Shield)

Osteo Bi-Flex (Triple Strength + Joint Shield)

Genuinely mixed: the NIH GAIT trial was negative overall while the MOVES trial found the combination comparable to celecoxib, and recent meta-analyses are modestly favorable. The mortality and cardiovascular associations are observational with a published selection-bias critique — not a proven longevity benefit. Safety across trials is excellent.

Triple Strength provides about 1,500 mg/day glucosamine HCl plus a chondroitin/MSM complex and 100 mg/day 5-LOXIN Boswellia serrata; the key Boswellia trial (Sengupta 2008) tested 100 and 250 mg/day, standardized to 30% AKBA.

This combination isn't obtainable from a normal diet: Boswellia serrata is an herbal tree resin with no food source at all, glucosamine comes from shellfish shells, and chondroitin only from animal cartilage.

Chondroitin sulfate plus glucosamine matched celecoxib, cutting WOMAC pain ~50% at 6 months with a good safety profile.


Glucosamine Chondroitin MSM (with OptiMSM)

Moderate evidence for knee-osteoarthritis symptom relief, strongest for pharmaceutical-grade products and moderate-to-severe pain; small trials suggest MSM adds benefit. Major guidelines disagree (OARSI and ACR advise against, ESCEO recommends prescription-grade). Mortality signals are observational and likely confounded.

The GAIT (Clegg 2006) and MOVES trials used glucosamine HCl 500 mg three times daily (1,500 mg/day) plus chondroitin sulfate 400 mg three times daily (1,200 mg/day); combo products often add 1,000–3,000 mg/day MSM.

Not meaningfully food-derived: bone broth and cartilage supply some glucosamine and chondroitin but in variable, unstandardized amounts far below the studied doses, and dietary MSM is only trace.


Weak-to-moderate: small, short, mostly industry-funded trials report modest knee-symptom benefits, and one well-run prevention trial was negative. Safety is a genuine strength (GRAS; well tolerated up to ~6 g/day). Claims beyond joint comfort, exercise recovery and skin are not well supported.

Knee-osteoarthritis trials used MSM about 1.5–6 g/day for 12 weeks; the most-cited trial (Kim 2006) used 3 g twice daily (6 g/day), and exercise-recovery studies used roughly 1.5–3 g/day.

MSM occurs in food only at trace levels (milk ~2–6 ppm, coffee ~1.6 ppm), so dietary intake is a few milligrams a day — roughly 1,000× below the multi-gram studied doses.


Evidence is claim-specific and mostly discouraging: small ulcerative-colitis trials looked promising but both large 2024 phase 3 trials failed, and Cochrane found no clear benefit of lecithin for dementia. A 2025 sarcopenia-cognition signal is hypothesis-generating only, and gut conversion of PC to TMAO is an unresolved cardiovascular concern.

Adequate Intake for choline is 550 mg/day (men) and 425 mg/day (women); supplements supply choline as phosphatidylcholine, which is about 13% choline by weight, so ~1,000 mg PC yields ~130 mg choline.

Choline is abundant in food: one large egg yolk has ~150 mg and 3 oz beef liver over 350 mg, with phosphatidylcholine the main dietary form (~40% of intake), so a few eggs can approach daily needs.

Ectopic boosting of phosphatidylcholine via diet restored late-life mitochondrial integrity in nematodes and reinstated metabolic resilience in human cell cultures — identifying PC decline as a malleable driver of mitochondrial aging.