Ingredient · Updated 2026-08-17
L-theanine
γ-glutamylethylamide · tea amino acid
Alone, L-theanine is a mild relaxant with mixed cognition data. With caffeine, several RCTs show cleaner attention than caffeine alone. Most matcha servings deliver tens of milligrams, not the 100–200 mg used in capsules.
- Study-dose band
- 100–200 mg, usually with 40–150 mg caffeine
- Typical bottle
- 20–60 mg in a tea serving; 100–200 mg in nootropic capsules
Evidence by outcome
| Outcome | Grade | Note |
|---|---|---|
| Attention with caffeine | B | Haskell 2008 and follow-ups: 97 mg theanine + 40–50 mg caffeine improved accuracy on attention tasks. |
| Anxiety reduction alone | C | Some positive trials at 200 mg; heterogeneity is high and several studies are small. |
Safety
- Well tolerated at supplemental doses used in trials.
- Can lower blood pressure slightly; caution with antihypertensives is reasonable.
Unknowns
- Matcha brands almost never assay L-theanine. Shade-grown tea is richer, but the milligrams are still an estimate unless lab-tested.
Questions
Does 2 g of matcha equal a theanine study dose?
Usually no. Two grams of matcha might provide roughly 20–40 mg of L-theanine. Capsule trials used 100–200 mg.
Sources
Formulas on this desk
- Matcha Extreme — A disclosed 2.25 g matcha serving with spirulina, cactus fruit, and acerola. A cup of tea with extras — not a high-dose EGCG trial.