Supplements
L-Theanine
Evidence ratingModerate
An amino acid found in green tea, research suggests it increases alpha-wave activity to promote calm focus without sedation. Combined with caffeine, it may attenuate jitteriness and anxiety while preserving alertness. Evidence for standalone strength or performance benefits is limited; it is most studied as part of a caffeine stack.
An ingredient with growing research
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Effects reported in research
May reduce caffeine-induced anxiety and jitteriness while maintaining alertness (research-based)
Alpha-wave increases suggest a state of relaxed focus without drowsiness
Some studies suggest reductions in perceived fatigue and subjective stress
Dosage & timing
- 100–200 mg when taken alone.
- When stacking with caffeine, a 2:1 ratio (200 mg theanine to 100 mg caffeine) is most commonly used in research.
- No stimulant effect has been reported, making pre-sleep use feasible.
Cautions
- •Generally regarded as safe, but long-term data on high-dose use is limited.
- •Consult a doctor before use if pregnant, breastfeeding, or taking antihypertensive medication.
- •Those prone to low blood pressure should be aware of a potential additional blood-pressure-lowering effect.
Supporting research
Last checked: 2026-06-26