Ingredient · focus
L-theanine
Focused calm without the jitters.
Evidence · Strong9 RCTs3 meta-analysises
The evidence
For
focus
Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Nutrition reviews · 2025
Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis.
Nutrition reviews · 2014
The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review.
Plant foods for human nutrition (Dordrecht, Netherlands) · 2020
For
stress
Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill.
Stress (Amsterdam, Netherlands) · 2024
Effect of Combined Ingestion of L-Theanine and L-Arginine for Short-Term Psychological Stress in Young Adults: A Randomized Placebo-Controlled Study.
Journal of nutritional science and vitaminology · 2022
Matcha consumption maintains attentional function following a mild acute psychological stress without affecting a feeling of fatigue: A randomized placebo-controlled study in young adults.
Nutrition research (New York, N.Y.) · 2021
Typical dose range
Within evidence-supported amounts. Start at the low end and titrate up only if needed.
100–200 mg
as needed
Limited safety data in pregnancy — defer to clinician guidance.
What to expect
Effect timing depends on the goal — check the evidence cards above for goal-specific notes.