L-Theanine

Tier 2 — promising · Relaxation · Focus · Sleep

Promotes calm, alert focus without drowsiness by boosting alpha brain waves. Pairs exceptionally well with caffeine (200 mg theanine : 100 mg caffeine) — the combination has been repeatedly shown in RCTs to improve sustained attention and accuracy while reducing caffeine-related jitteriness and anxiety. Smaller trials (e.g. Lyon 2011, Rao 2015, Hidese 2019) suggest improvements in sleep quality and perceived stress, though the literature is still modest. Found naturally in green tea. One of the safest supplements known.

Dose: Focus: 100–200 mg + 50–100 mg caffeine; Sleep: 200–400 mg standalone, 30–45 min before bed