Glycine
Glycine is the smallest and simplest amino acid, found abundantly in collagen-rich foods like bone broth, skin, and connective tissue. It serves as a building block for proteins, a precursor to the antioxidant glutathione, and an inhibitory neurotransmitter in the brainstem and spinal cord. It has gained particular attention for its ability to promote restful sleep without disrupting normal sleep architecture.
Expert Evidence
12 references from 2 experts
“I personally take glycine as part of my sleep supplement. It's got 2,500 mg of glycine on its own, but the sleep supplement also includes magnesium in the form of magnesium glycinate, which yields an additional 774 mg of glycine. So I'm taking just over 3,200 mg of glycine in my sleep supplement.”
Glycine Helps to Fix Sleep
3:4310 references in 4 episodes from 2022–2025
Brad Stanfield personally takes glycine as a core part of his sleep supplement and views it favorably for sleep quality and next-day cognitive performance. He highlights its safety profile, noting it doesn't disrupt sleep architecture, and also discusses its role alongside NAC for aging-related benefits. No cautions or reasons to avoid glycine were discussed.
Consumption
He takes just over 3,200 mg of glycine nightly as part of his sleep supplement — 2,500 mg of glycine plus an additional 774 mg from magnesium glycinate.
Benefits
Glycine improved next-day liveliness, clear-headedness, and memory while reducing fatigue, and importantly did not disrupt normal sleep architecture. Combined with NAC in older adults, it also improved glutathione levels, mitochondrial function, and physical function.
Best Practices
Sleep studies consistently used about 3,000 mg taken shortly before bedtime, and a recent review recommended 1.5–3 grams per day for general needs. For the GlyNAC combination targeting aging, doses were much higher at 100 mg/kg body weight.
“There's certain supplements that I use to sleep as well. I'm a fan of glycine, ashwagandha, magnesium L-threonate, and just straight mag oxide as well.”
Dr. Peter Attia on Mastering Longevity – Insights on Cancer Prevention, Heart Disease, and Aging
3:45:432 references in 2 episodes from 2016–2023
Rhonda Patrick takes glycine as part of her sleep supplement stack alongside ashwagandha and magnesium. She highlights its dual role as an anti-inflammatory signaling molecule and inhibitory neurotransmitter, noting its abundance in hydrolyzed collagen powder. No specific dosage, timing, or cautions are discussed.
Side Effects
- Mild nausea at high doses
- Soft stools
- Rare reports of drowsiness during daytime use
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