Remedy · supplement
L-theanine
Also: theanine
A green-tea amino acid studied for stress.
Evidence by condition
Each grade reflects the research for L-theanine and that condition specifically.
- CAnxiety & stress
May reduce stress in healthy adults; weak evidence for diagnosed anxiety disorders.
1 citation
- L-Theanine MSK About Herbs · accessed 2026-06-21
- L-Theanine
- CInsomnia
Around 200 mg/day modestly improves subjective sleep quality and sleep latency; effects on objective sleep are inconsistent and many positive trials used combination products.
2 citation s
- The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis Meta-analysis 2025 · n=897 · Sleep Medicine Reviews · PMID 40056718 · DOI 10.1016/j.smrv.2025.102076
- Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial Randomized trial 2019 · n=30 · Nutrients · PMID 31623400 · DOI 10.3390/nu11102362
- The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis