Rankings / Cognitive — Nootropics
L-theanine
Cognitive · Amino acid (tea-derived)
Tier B
What this is
Combination with caffeine is the most evidence-backed nootropic stack — Camfield 2014 meta-analysis showed moderate improvements in attention switching/accuracy in first 2 hours post-dose. Ratio typically 2:1 theanine:caffeine.
Mechanism
Non-proteinogenic amino acid from tea; crosses BBB; increases alpha brain waves; mild GABA agonism; glutamate receptor modulation; calming without sedation
Dose & route
100-400 mg/day; commonly 100-200 mg paired with caffeine
Citations
- https://pubmed.ncbi.nlm.nih.gov/24946991/
- https://pubmed.ncbi.nlm.nih.gov/40314930/
- https://www.mdpi.com/2077-0383/14/21/7710
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This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.