Source: Examine.com — Theanine — 100–200 mg for calm focus, frequently paired 1:2 with caffeine.
A calming amino acid found in tea that produces relaxed alertness without sedation.
Increases alpha brain waves and calming neurotransmitters like GABA.
A single 200 mg dose improved choice reaction time and attention; effects on mood were smaller and less certain.
Meta-analysis of 31 RCTs · n=~1,200 · 200 mg — 2026 — Molecular Psychiatry (meta-analysis)
L-theanine with caffeine improved attention and reduced task-related jitter versus either alone.
Double-blind crossover RCT · n=27 · 200 mg ± 160 mg caffeine — Kahathuduwa et al., 2018 — Nutr Neurosci
Reduced perceived stress and improved sleep quality and attention over 28 days in moderately stressed adults.
28-day double-blind RCT · n=98 · 200 mg/day — 2024 — Nutrients (AlphaWave RCT)
Bottom line: Good evidence that 200 mg — especially paired with caffeine — sharpens attention and takes the edge off jitters. The effects are real but subtle, and there's essentially no downside, which makes it low-risk to try.
Very safe with no known downsides at normal doses. Pairs 1:2 with caffeine (e.g., 100 mg caffeine + 200 mg theanine).
Anecdotes, not evidence, and not medical advice. Frequency labels are our read of forum sentiment, not a formal survey. Individual responses vary widely.
| Per serving | |
|---|---|
| Typical branded single-ingredient product | $0.42 |
| Bulk powder at the clinical dose (250g, $24.97) | $0.02 |
Buying bulk powder instead of a branded bottle saves about 95% per serving.
Bulk price: $24.97/250g → Alt source: $9.99/125gEducational only — not medical advice. Grades and clinical doses are computed from public labels against sourced research (citations on the main site); prices last verified 2026-07-21. Expensive Powder has no sponsors; bulk links may earn an affiliate commission, which never affects a grade. Talk to a clinician before starting any supplement.