L-Theanine
Also known as: theanine, Suntheanine
An amino acid found naturally in green tea that promotes a calm, focused state without sedation. It is widely paired with caffeine to smooth out jitters, and used on its own in stress and sleep formulas. Effects are noticeable within about an hour of a single dose.
Research summary
Increases alpha-wave activity and modulates glutamate and GABA signaling.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 50 mg | 100–200 mg | 400 mg | — |
100–200 mg is the standard single dose; a 2:1 theanine-to-caffeine ratio (e.g., 200 mg theanine with 100 mg caffeine) is the most common focus pairing. Higher doses (400 mg) appear in sleep formulas.
Source material: fermentation-derived or green tea extract
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Mild taste; works well in gummies and powders.
Formulation notes
Pairs with caffeine for focus; with magnesium and apigenin for sleep.
Sources
- Theanine — ExamineExamine
- The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review (Williams 2020)PubMed
- Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials (Gerolymos 2026)PubMed
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