--- title: "Evidence: collagen and methylation substrate" description: "Glycine supplementation can reduce daytime sleepiness and fatigue and improve vigilance after acute sleep restriction, possibly by modulating SCN function." url: "https://magellanlongevity.com/study/s125.md" canonical: "https://magellanlongevity.com/study/s125.html" html: "https://magellanlongevity.com/study/s125.html" type: "study" study_key: "s125" journal: "Front Neurol" year: 2012 pmid: "22529837" doi: "10.3389/fneur.2012.00061" citations: 1 updated: 2026-09-02 author: "Gabriel Radu, DO" author_credentials: "Physiatrist (PM&R). NY medical license 275110. NPI 1376861765." publisher: "Magellan Longevity" content_format: "markdown" --- # Evidence: collagen and methylation substrate [Home](https://magellanlongevity.com/) › [Research map](https://magellanlongevity.com/longevity-research-map.html) › Evidence: collagen and methylation substrate **HTML version:** https://magellanlongevity.com/study/s125.html · **In the Magellan app:** https://magellanlongevity.com/#/study/s125 ## Citation | Field | Value | | --- | --- | | Journal | Front Neurol | | Year | 2012 | | PMID | [22529837](https://pubmed.ncbi.nlm.nih.gov/22529837/) | | DOI | [10.3389/fneur.2012.00061](https://doi.org/10.3389/fneur.2012.00061) | | Study key | s125 | ## Takeaway Glycine supplementation can reduce daytime sleepiness and fatigue and improve vigilance after acute sleep restriction, possibly by modulating SCN function. ## The question Does glycine improve daytime sleepiness, fatigue, and performance in sleep-restricted healthy subjects, and does it affect circadian rhythms? ## Hypothesis Glycine may improve sleep quality and reduce daytime sleepiness and fatigue, potentially by modulating circadian rhythms. ## Methods Healthy subjects with sleep restricted to 25% less than usual for three nights ingested 3g of glycine or placebo before bedtime. Daytime sleepiness and fatigue were assessed using a visual analog scale (VAS) and a questionnaire. Performance was evaluated using a PC performance test program. Additionally, plasma melatonin and the expression of circadian-modulated genes in the rat suprachiasmatic nucleus (SCN) were measured to assess effects on circadian rhythms. ## Results In subjects given glycine, VAS data showed a significant reduction in fatigue and a tendency toward reduced sleepiness. The questionnaire also indicated improved daytime sleepiness and fatigue. PC performance tests revealed significant improvement in psychomotor vigilance. Glycine did not significantly affect plasma melatonin concentrations or the expression levels of clock genes like Bmal1 and Per2. However, a glycine-induced increase in neuropeptides arginine vasopressin and vasoactive intestinal polypeptide was observed in the light period. ## Conclusion Glycine improves daytime sleepiness and fatigue induced by acute sleep restriction and enhances psychomotor vigilance. While it did not alter the circadian clock directly, glycine modulated SCN function by increasing certain neuropeptides, which may indirectly contribute to its beneficial effects on sleepiness and fatigue. ## Limitations The study involved acute sleep restriction and did not observe direct alterations in the circadian clock itself, suggesting an indirect mechanism for glycine's effects on sleepiness and fatigue. ## Verbatim from the abstract > glycine improves daytime sleepiness and fatigue induced by acute sleep restriction ## Where this study is used on Magellan This paper is one of the citations behind the evidence grade on the pages below. Grades are assigned from the published research and are independent of affiliate commissions. | Compound or device | Evidence grade | Graded pages | | --- | --- | --- | | All-in-One Longevity Formulation | Emerging evidence | [NOVOS Core All-In-One Sachets](https://magellanlongevity.com/p/12.md) | | Glycine Powder | Moderate evidence | [Glycine Powder](https://magellanlongevity.com/p/125.md) | ## Reference 1. **Evidence: collagen and methylation substrate** Front Neurol 2012 · [PMID 22529837](https://pubmed.ncbi.nlm.nih.gov/22529837/) · [DOI 10.3389/fneur.2012.00061](https://doi.org/10.3389/fneur.2012.00061) > glycine improves daytime sleepiness and fatigue induced by acute sleep restriction ## Structured data ```json {"@context":"https://schema.org","@graph":[{"@type":"MedicalWebPage","@id":"https://magellanlongevity.com/study/s125.html#page","url":"https://magellanlongevity.com/study/s125.html","name":"Evidence: collagen and methylation substrate","description":"Glycine supplementation can reduce daytime sleepiness and fatigue and improve vigilance after acute sleep restriction, possibly by modulating SCN function.","inLanguage":"en","isPartOf":{"@type":"WebSite","name":"Magellan Longevity","url":"https://magellanlongevity.com/"},"author":{"@type":"Person","name":"Gabriel Radu, DO","jobTitle":"Physiatrist (PM&R)","identifier":[{"@type":"PropertyValue","name":"NPI","value":"1376861765"},{"@type":"PropertyValue","name":"NY medical license","value":"275110"}]},"publisher":{"@type":"Organization","name":"Magellan Longevity","url":"https://magellanlongevity.com/"},"encoding":{"@type":"MediaObject","encodingFormat":"text/markdown","contentUrl":"https://magellanlongevity.com/study/s125.md"},"dateModified":"2026-09-02"},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://magellanlongevity.com/"},{"@type":"ListItem","position":2,"name":"Research map","item":"https://magellanlongevity.com/longevity-research-map.html"},{"@type":"ListItem","position":3,"name":"Evidence: collagen and methylation substrate","item":"https://magellanlongevity.com/study/s125.html"}]},{"@type":"ScholarlyArticle","@id":"https://magellanlongevity.com/study/s125.html#study","name":"Evidence: collagen and methylation substrate","headline":"Evidence: collagen and methylation substrate","datePublished":"2012","isPartOf":{"@type":"Periodical","name":"Front Neurol"},"identifier":"PMID:22529837","url":"https://pubmed.ncbi.nlm.nih.gov/22529837/","sameAs":"https://doi.org/10.3389/fneur.2012.00061","abstract":"Glycine supplementation can reduce daytime sleepiness and fatigue and improve vigilance after acute sleep restriction, possibly by modulating SCN function."}]} ``` ## Related on Magellan Longevity - [Glycine Powder](https://magellanlongevity.com/p/125.md) — product graded on this and related evidence - [NOVOS Core All-In-One Sachets](https://magellanlongevity.com/p/12.md) — product graded on this and related evidence - [The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in…](https://magellanlongevity.com/study/nmn_trial.md) - [Caloric restriction, resveratrol and melatonin: Role of SIRT1 and implications for aging…](https://magellanlongevity.com/study/resv_sirt1.md) - [Induction of autophagy by spermidine promotes longevity.](https://magellanlongevity.com/study/spermidine_autophagy.md) - [Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the…](https://magellanlongevity.com/study/akg_krebs.md) - [Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione…](https://magellanlongevity.com/study/glutathione_glynac.md) - [Longevity research map](https://magellanlongevity.com/longevity-research-map.html) - [Evidence-based longevity supplements](https://magellanlongevity.com/longevity-supplements.md) ## Scope and disclosures Educational information, not medical advice. Nothing here is intended to diagnose, treat, cure, or prevent any disease. Talk to your physician before starting any supplement or device, especially if you are pregnant, nursing, or taking medication. Editorial firewall: evidence grades are assigned from the published research and are independent of any affiliate commission. As an Amazon Associate, Magellan Longevity earns from qualifying purchases. Reviewed for accuracy by a board-certified physician (DO).