Glycine Powder, graded Moderate-evidence on Magellan — small human trials report that about 3 g of glycine before bedtime improves subjective sleep quality and reduces next-day fatigue and sleepiness after partial sleep restriction, with mechanistic work attributing these effects to NMDA-receptor-mediated thermoregulation in the suprachiasmatic nucleus. Evidence for collagen-related benefits is mixed, since glycine-rich gelatin can raise collagen-synthesis markers while at least one controlled trial found no added benefit.
Source: Front Neurol 2012, PMID 22529837 ↗ · Nutraceuticals & Cellular Energizers · How Magellan grades evidence · Study write-up · evidence confidence: high
Glycine is the smallest and simplest proteinogenic amino acid, synthesized endogenously but often in amounts below full metabolic demand. It is a major building block of collagen, comprising roughly one-third of the collagen molecule, and serves as a substrate for glutathione, creatine, heme, and one-carbon (methylation) metabolism via glycine N-methyltransferase. In the nervous system glycine acts both as an inhibitory neurotransmitter at glycine receptors and as a co-agonist at NMDA-type glutamate receptors. Taken orally before bed, glycine lowers core body temperature through peripheral vasodilation, a change associated with the onset of sleep.
Small human trials report that about 3 g of glycine before bedtime improves subjective sleep quality and reduces next-day fatigue and sleepiness after partial sleep restriction, with mechanistic work attributing these effects to NMDA-receptor-mediated thermoregulation in the suprachiasmatic nucleus; these studies are small and several were industry-affiliated. As a precursor of glutathione, glycine combined with cysteine or N-acetylcysteine (GlyNAC) has restored glutathione synthesis and improved oxidative stress, mitochondrial function, inflammation, insulin resistance, muscle strength, and other aging hallmarks in older adults—but those placebo-controlled trials are small (about two dozen participants), come from a single research group, tested the combination rather than glycine alone, and benefits faded after supplementation stopped. Evidence for collagen-related benefits is mixed, since glycine-rich gelatin can raise collagen-synthesis markers while at least one controlled trial found no added benefit. This evidence describes glycine and its mechanisms (and, in several trials, glycine combined with other compounds), not this specific commercial product.
Peer-reviewed studies on the active compound — citations link to PubMed.
“glycine improves daytime sleepiness and fatigue induced by acute sleep restriction”
“glycine ingestion before bedtime significantly improved subjective sleep quality”
“We recently reported that glycine ingestion before bedtime significantly ameliorated subjective sleep quality in individuals with insomniac tendencies.”
“These data suggest that exogenous glycine promotes sleep via peripheral vasodilatation through the activation of NMDA receptors in the SCN shell.”
“CP supplementation did not influence sleep quantity, latency, or efficiency, but reduced awakenings and improved cognitive function in physically active males with sleep complaints.”
“The intervention trial reduced sleep onset latency (-24 ± 25 min; P = 0.002), increased total sleep time (22 ± 32 min; P = 0.01), and increased sleep efficiency (2.4% ± 3.9%; P = 0.03), while also reducing morning sleepiness ( P = 0.02).”
Research describes the active mechanism and is not a claim about this specific product.
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Yes — its active compound is linked to 18 peer-reviewed studies, summarized and cited above.
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