NutriStack
Glycine and L-Theanine, a synergy.
Both amino acids support sleep through different routes, so combining them may reduce pre-sleep tension and improve sleep quality more than either alone.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Glycine and L-Theanine
- Pair type
- Synergy
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Synergy · Emerging evidence
Synergy
What is happening. Both amino acids support sleep through different routes, so combining them may reduce pre-sleep tension and improve sleep quality more than either alone.
Mechanism. L-theanine increases GABA and alpha activity to lower arousal, while glycine activates NMDA receptors in the suprachiasmatic nucleus, promoting peripheral vasodilation and a drop in core body temperature that facilitates sleep onset.
Recommendation. Take together before bed, for example L-theanine 100 to 200 mg with glycine 3 g. Both are well tolerated and need no timing separation.
Sources (2)
- Kawai N, Sakai N, Okuro M, et al. The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology. 2015
- Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition. 2008
Stack Score
How this pair moves the number.
Effect on the composite score
If both Glycine and L-Theanine are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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