Glycine
The simplest amino acid — and one of the most underrated for sleep, collagen, and healthy ageing. Cheap, effective, and backed by growing research.
Glycine is a small amino acid that punches above its weight. At bedtime, 3 g improves your sleep quality by lowering your core body temperature — the same mechanism your body uses naturally to initiate sleep. Beyond sleep, glycine is essential for collagen synthesis, glutathione production (your body's master antioxidant), and has emerging longevity benefits.
Good for you if: You want better sleep quality (not just more sleep), support your joints and skin, boost glutathione, or are interested in longevity-focused supplementation.
Dive deeper into the researchCommon side effects
- Almost no side effects at recommended doses
- Very high doses (15+ g) can cause mild GI upset
- Sweet taste makes it easy to take
What does glycine do?
To fall asleep, your body needs to drop its core temperature by about 1°C. Glycine helps this happen by increasing blood flow to your extremities (hands and feet), which radiates heat away from your core. It also acts on NMDA receptors in the hypothalamus to promote sleep onset.
But glycine does much more than sleep. It's a building block for collagen (your skin, joints, and connective tissue) and glutathione (your body's most important antioxidant). In longevity research, glycine supplementation has extended lifespan in animal models and is being studied as a key component of healthy ageing.
What can you expect?
- Better sleep quality — deeper, more restorative sleep from the first night
- Less next-day fatigue — even after short sleep, glycine improves how you feel the next day
- Healthier skin and joints — glycine makes up 1/3 of collagen
- Better detox capacity — glutathione production improves
- Anti-inflammatory effects — glycine dampens inflammatory signalling
How to take it
3 g about 30–60 minutes before bed. Mix the powder directly in water — it has a pleasant, slightly sweet taste. You can also add it to herbal tea.
For collagen and longevity benefits, some people take an additional 2–3 g during the day.
How long to take it: Sleep effects are often noticeable from night one. Collagen and longevity benefits develop over weeks to months. Safe for indefinite daily use.
Which form to buy?
| Form | Dose | Notes |
|---|---|---|
| Pure glycine powder | 3–5 g/day | Best value; sweet taste, dissolves easily |
| Capsules | 1000 mg each | Convenient; need 3 capsules for sleep dose |
| GlyNAC (glycine + NAC) | 1.2 g each, twice daily | Longevity combo studied by Baylor researchers |
Pure glycine powder is extremely affordable: ₹300–600 for 250 g (lasts 2+ months). Available from NOW Foods, Bulk Supplements, and various Indian sports nutrition brands.
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Get early accessFrequently Asked Questions
How does glycine improve sleep?
Glycine lowers your core body temperature by increasing blood flow to your extremities. Your body naturally drops its temperature to initiate sleep, so glycine accelerates this process. It also acts on NMDA receptors in the hypothalamus. Studies show 3 g before bed reduces time to fall asleep and improves next-day alertness.
What is GlyNAC and why is it popular for longevity?
GlyNAC is a combination of glycine and N-acetyl cysteine (NAC). Baylor College researchers showed it replenishes glutathione in older adults, reversing markers of oxidative stress and improving mitochondrial function. The standard dose is 1.2 g of each, twice daily.
Can glycine help with collagen production?
Absolutely. Glycine makes up about one-third of collagen's amino acid content. Your body uses glycine along with proline and vitamin C to synthesise collagen. Supplementing provides the raw material for skin, joint, tendon, and gut barrier repair.
Is glycine safe to take every night?
Yes. Glycine is a naturally occurring amino acid found in protein-rich foods. At 3–5 g/day, there are no reported safety concerns even with long-term daily use. It's one of the safest supplements available.
How it works in your body
Glycine acts on multiple systems. For sleep, it binds to NMDA receptors in the suprachiasmatic nucleus (your brain's master clock) and promotes vasodilation in peripheral blood vessels, lowering core body temperature. This thermoregulatory effect is the primary driver of its sleep benefits.
For longevity, glycine is rate-limiting for glutathione synthesis (along with cysteine from NAC). Glutathione is your body's master antioxidant — protecting mitochondria, enabling detoxification, and modulating inflammation. Levels decline with age, and supplementing the precursors (GlyNAC) has been shown to reverse this decline in clinical studies.
What the studies show
- Sleep: 3 g before bed improved subjective sleep quality and next-day alertness (Japanese clinical trials)
- Glutathione: GlyNAC supplementation restored glutathione levels in older adults (Baylor College)
- Inflammation: Glycine reduces inflammatory cytokines (TNF-α, IL-6) through NF-κB modulation
- Collagen: Glycine + vitamin C improved collagen synthesis rates in controlled studies
- Longevity: Extended lifespan in multiple animal models; human trials ongoing
Side effects & safety
- Essentially no side effects at 3–5 g/day. One of the safest supplements available.
- High doses (15+ g) — may cause mild nausea or soft stools.
- Drug interactions — Clozapine (an antipsychotic) may be affected. Consult your doctor if relevant.
- Pregnancy — Glycine is naturally present in food and considered safe, but check with your OB/GYN for supplement doses.
Which labs to check
- Glutathione (reduced) — to track antioxidant status, especially with GlyNAC
- hsCRP — general inflammation marker
- Fasting glucose & HbA1c — glycine may have mild glucose-lowering effects
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