Comparison
L-Theanine vs Caffeine
L-Theanine
Unique amino acid found almost exclusively in tea leaves. Promotes calm, focused attention. Synergistic with caffeine.
Caffeine
The world's most widely consumed psychoactive substance. Adenosine receptor antagonist enhancing alertness and attention.
| Field | L-Theanine | Caffeine |
|---|---|---|
| Category | amino-acid | stimulant |
| Dose range | 100–400mg | 50–400mg |
| Half-life | 1h | 5h |
| Onset | 30min | 30min |
| Evidence | EVIDENCEA | EVIDENCEA |
| Safety | ●●●●● | ●●●●○ |
| Legal (US) | USOTC | USOTC |
| PubMed refs | 720 | 25000 |
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