Simple amino acid that improves sleep quality, supports collagen synthesis, and may promote longevity
Glycine is one of the simplest, cheapest, and most underrated sleep supplements. Taking 3g before bed consistently improves subjective sleep quality, reduces time to fall asleep, and helps you wake feeling more refreshed, with virtually no side effects.
The mechanism is elegant: glycine lowers core body temperature, which is a key signal for sleep initiation. It also acts on NMDA receptors in the brain's sleep centers and may increase serotonin availability.
Beyond sleep, glycine is a building block for collagen (every third amino acid), a precursor to glutathione (master antioxidant), and has been shown to extend lifespan in animal models by mimicking methionine restriction.
At $0.10-0.30/day with essentially no downside, glycine is worth trying for anyone with sleep issues or interested in longevity. It's the rare supplement where the risk/reward ratio is strongly favorable.
Science & Mechanisms
How Glycine Improves Sleep:
- Thermoregulation - Glycine causes peripheral vasodilation, which dissipates heat from the body's core. This drop in core temperature is a critical signal for sleep onset. Studies show glycine reduces core body temperature by ~0.5°C.
- NMDA Receptor Modulation - Glycine acts on NMDA receptors in the suprachiasmatic nucleus (the brain's master clock), promoting sleep through neural mechanisms.
- Serotonin Pathway - Glycine may increase serotonin availability in the brain, supporting both sleep and mood.
Clinical Evidence:
- Yamadera et al. (2007): 3g glycine improved subjective sleep quality and reduced daytime sleepiness in people with sleep complaints
- Bannai et al. (2012): 3g glycine improved next-day cognitive performance in sleep-restricted subjects
- Kawai et al. (2015): Confirmed NMDA receptor mechanism in suprachiasmatic nucleus
Longevity Mechanisms:
- Methionine restriction mimetic - Glycine may counteract excess methionine (common in high-protein diets), activating longevity pathways
- Glutathione precursor - Combined with NAC (as "GlyNAC"), supports master antioxidant synthesis
- Collagen synthesis - Glycine is 33% of collagen; supplementation supports structural protein maintenance
- Autophagy activation - May promote cellular cleanup mechanisms
Animal Evidence:
- Glycine extended lifespan by 4-6% in genetically diverse mice
- GlyNAC extended lifespan by 24% in mice
Episodes
Andrew Huberman hosts Dr. Craig Koniver, a board-certified physician specializing in performance medicine, for a deep dive into the therapeutic use of peptides and hormones for ...
Chris Masterjohn explores the calming effects of glycine supplementation, particularly its role in reducing the startle response and supporting nervous system regulation. He rev...
Yale-educated biochemist Dr. Joel Brind joins Morning Air to explain his theory that chronic inflammation is driven by widespread glycine deficiency rather than being a normal r...
Nutritionist Dee McCaffrey covers glycine's wide-ranging health benefits on this episode of Diet Science. She explains that glycine serves as a building block for glutathione, t...
Sal DiStefano, Adam Schaefer, and Justin Andrews rank their top seven underrated supplements that most fitness enthusiasts overlook. The list covers vitamin D (cheap, widely def...