Supplements · Sleep & Skin
Glycine supplement: sleep, collagen, and midlife benefits
Glycine is a conditionally essential amino acid — the body makes some, but often not enough. It's the primary building block of collagen and functions as an inhibitory neurotransmitter that improves sleep quality. In midlife women, both roles matter.
Sleep evidence
Multiple RCTs (Yamadera et al., 2007; Bannai et al., 2012) show 3g glycine before bed reduces subjective and objective sleep latency and improves next-day cognitive performance. Mechanism: modest reduction in core body temperature via peripheral vasodilation.
Collagen and skin
Roughly one-third of collagen is glycine. If you take hydrolyzed collagen peptides (10–15g/day), you're already getting a large glycine dose. Standalone glycine is more targeted for the sleep effect.
Dosing that matches the trials
- Sleep: 3g dissolved in water 30–60 min before bed
- Glutathione support: 3–5g/day with N-acetylcysteine
- Skin/collagen synergy: paired with 10–15g collagen peptides + vitamin C
Who benefits most
Women in perimenopause with fragmented sleep, low protein intake, or elevated inflammatory markers. Glycine intake from a typical Western diet is often below the amount needed to support collagen turnover during accelerated midlife bone and skin loss.
Frequently asked questions
What does glycine do?
It builds collagen, supports glutathione production (major antioxidant), regulates neurotransmission via glycine and NMDA receptors, and improves sleep quality.
How much glycine for sleep?
3 grams taken 30–60 minutes before bed. This dose has RCT evidence for improving sleep quality, reducing time to fall asleep, and reducing daytime fatigue.
Does glycine help with anxiety?
Modest evidence. Glycine has mild calming effects via NMDA receptor modulation, but is not a replacement for anxiety-specific treatments.
Is glycine safe long-term?
Yes. It's a naturally occurring amino acid with an excellent safety profile at typical supplemental doses.
Can I take glycine with other supplements?
Yes. It combines well with magnesium (for sleep) and with collagen peptides (which are ~30% glycine).
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Medically reviewed by Kindr Health Clinical Team · Last reviewed 2026-06-19. Compounded medications are prepared by FDA-registered 503A pharmacies and are not FDA-approved drug products.