L-Theanine 200 mg, 120 Capsules
Single-ingredient capsules stating milligrams per capsule, which makes the per-serving amount straightforward.
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L-theanine
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Ingredient evidence
L-theanine is an amino acid derived from tea. A 2026 systematic review and meta-analysis of 31 randomized trials found a short-term attention benefit in healthy adults, while effects on stress, anxiety, fatigue, and depressive symptoms were smaller, inconsistent, or less certain. Molecular Psychiatry: Systematic review of L-theanine
Meaningful variation
The trials used different populations, outcomes, schedules, and amounts, so one result should not be generalized to every product or purpose. Some products also combine L-theanine with caffeine, which makes it harder to attribute an effect to L-theanine alone.
Product facts
2 products
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L-Theanine 200 mg, 240 Capsules
The same stated amount per capsule in a larger count. Check cost per capsule rather than per bottle.
Shopping for a goal? This ingredient appears under Sleep and stress.