Cheap amino acid with better sleep and glutathione-precursor benefits.
One of the most underrated supplements. Extremely cheap, extremely safe, real benefits in sleep and glutathione status.
Glycine (Glycine) is a amino acid / glutathione support with evidence grade B, meaning it is supported by human RCTs. We track 9 products containing Glycine. Typical doses range from 300 to 5000 mg per serving. The top-ranked product scores 7.6 out of 10 on our composite scale (dose, evidence, price, testing, transparency). Prices range up to $99.00 per month.
| Product | Brand | Dose | Price/mo | 3rd-party tested | Score |
|---|---|---|---|---|---|
| Glycine Powder | BulkSupplements | 3000 mg | $20.00 | Yes | 7.6 |
| Glycine Supplement | Double Wood Supplements | 1000 mg | $19.95 | Yes | 7.6 |
| Daily Longevity Blend | AgeMate | 700 mg | $69.00 | Yes | 7.0 |
| Longevity Mix - Blood Orange | Blueprint | 2000 mg | $49.00 | Yes | 6.7 |
| AGZ: Nightly Sleep Support | AG1 (Athletic Greens) | 2000 mg | $99.00 | Yes | 6.7 |
Scores are editorial judgments, not a scientific standard. See how we score.
The simplest amino acid, sweet-tasting, found in bone broth and collagen. Your body uses it to make glutathione (your main antioxidant), collagen, and creatine.
Small trials show 3 g at bedtime improves sleep quality and next-day alertness. Combined with NAC (see GlyNAC), it restores glutathione levels in older adults and improves multiple aging markers.
One of the most underrated supplements. Extremely cheap, extremely safe, real benefits in sleep and glutathione status.
Simplest amino acid, α-carbon with H side chain. Precursor to glutathione (with cysteine and glutamate).
Kumar et al. 2021 (Clin Transl Med) demonstrated GlyNAC (glycine + NAC) restores glutathione and improves multiple biomarkers of aging. Bannai 2012 showed 3 g pre-sleep improved sleep quality.
~1 hour.
None major. Very sweet in powder form, mix in water or coffee.
When a product exceeds the UL or contains an ingredient with clinically significant interactions, a "Review advised" flag appears on its product page and links here.
The trial dose above is our editorial pick from the published human trials for this ingredient. We choose the dose that the best-available studies used on the endpoint most relevant to longevity. The range shows the lowest and highest doses tested in published trials. The landmark studies below are the papers we read to set it. You can click through and check our work.
When new trials publish, our automated sweeps flag them. If a new study materially changes the dose, we update it through editorial review and record the old dose, new dose, and the triggering study in every affected product's recommendation history. The dose is never changed automatically.
Regulatory events, evidence grade changes, and key research milestones for Glycine, most recent first. Studies link to the paper; regulatory entries name and link the responsible authority.
Verified 2026-07-05. We update this section as new peer-reviewed trials land.
Glycine's most consistently replicated human effect is improving subjective sleep quality when taken before bed. Multiple small randomized, double-blind, placebo-controlled crossover trials from the same Japanese research group found 3 g of glycine 30 minutes before bedtime improved subjective sleep quality, reduced sleep onset latency, and improved next-day fatigue and alertness, with effects appearing on the first night without tolerance developing over the study period (https://pmc.ncbi.nlm.nih.gov/articles/PMC3328957/). A 2024 GeroScience systematic review confirmed the sleep signal but flagged small sample sizes and high risk of bias, noting no independently replicated, adequately powered trial has been published. Combined with N-acetylcysteine as GlyNAC, glycine has stronger backing: a Baylor College of Medicine randomized clinical trial in 24 older adults over 16 weeks found GlyNAC corrected glutathione deficiency, lowered oxidative stress and inflammation, and improved gait speed, muscle strength, and six-minute walk distance versus placebo (https://pubmed.ncbi.nlm.nih.gov/35975308/).
Marketers often present glycine alone as an anti-aging or longevity compound based on the GlyNAC aging-reversal headlines, but nearly all of the dramatic aging-hallmark results (mitochondrial function, telomere-related markers, cellular senescence markers) come from the glycine-plus-NAC combination, not glycine by itself. A separate 114-person RCT testing glycine and NAC at three doses in healthy older adults found the combination did not significantly increase the primary glutathione endpoint in the study population as a whole, only in a subgroup with high baseline oxidative stress and low baseline glutathione (https://pubmed.ncbi.nlm.nih.gov/35821844/). For metabolic health, marketing claims often cite glycine's association with lower diabetes and heart disease risk in observational data as if it were proven causal and clinically actionable; an evidence review by Evidentia Nutrition states plainly that current interventional evidence does not support clinical use of glycine alone for glycaemic control, and that small trials showing HbA1c or fasting glucose improvements have not been replicated at scale.
3 g before bedtime for sleep; 5-15 g/day (often split into 3 doses) studied for metabolic outcomes
Glycine is generally recognized as safe by the FDA and has been well tolerated in trials up to 15 g/day, with psychiatric studies using up to 0.8 g/kg/day over 6-12 weeks without serious adverse events. GlyNAC combination trials in older adults reported no adverse events over 16 weeks (https://pubmed.ncbi.nlm.nih.gov/35975308/). Long-term safety beyond about 4-6 months has not been established in controlled human trials.
GlyNAC for 24 weeks restored glutathione and improved oxidative stress markers in older adults.
Read study →All products in our catalog that contain Glycine, ranked by our overall score. Ranking is editorial, never paid.
BulkSupplementsStatus as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
Double Wood SupplementsStatus as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
AgeMateMulti-ingredient bundle
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
BlueprintMulti-ingredient bundle
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
AG1 (Athletic Greens)Elemental vs compound: check label
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
Avea LifeMulti-ingredient bundle
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
Multi-ingredient bundle
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
NOVOS LabsMulti-ingredient bundle
Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
DoNotAgeStatus as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.
Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.
Molecules in the same class, plus the actives most often formulated alongside Glycine in our catalogue.
See Glycine in context: the mechanism it acts through, the biomarker it moves, the products that dose it, and the trials that tested it.
View Glycine on the Longevity Map →The simplest amino acid, sweet-tasting, found in bone broth and collagen. Your body uses it to make glutathione (your main antioxidant), collagen, and creatine.
The trial dose in published human studies is 3000 mg per day, with a range of 1000 to 10000 mg per day. Always consult a qualified clinician before starting any supplement.
No formal UL (EFSA/VKM Norway state there is insufficient data to derive one). Supplement doses of 3-10 g/day are considered safe; clinical trials have used up to 60 g/day without serious adverse effects, though very high doses (>500 mg/kg body mass) may cause cytotoxic, renal, or hepatic effects.
We track 9 products containing Glycine. The top-ranked product scores 7.6 out of 10 on our composite scale, which evaluates dose, evidence, price, third-party testing, and transparency. See the comparison table above. Scores are editorial judgments, not a scientific standard.
Glycine has evidence grade B, meaning it is supported by human RCTs. Grade A means replicated human RCTs with hard endpoints. Grade B means human RCTs with biomarker outcomes. Grade C means mixed or small human trials. See our evidence grading methodology.
Evidence grades are reviewed when new human RCTs are published. Product counts update automatically as new products are added. Dose ranges reflect published trial data, not brand recommendations. Read how we verify.
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