Guarana (Paullinia cupana)

Tier 3 — weak evidence · Energy · Cognition · Stimulant

An Amazonian seed with caffeine content 2-4x that of coffee beans (2-6% vs 1-2%), combined with theobromine, theophylline, tannins, and saponins. The tannin-bound caffeine releases more slowly than coffee, giving a longer, smoother stimulation with less crash. Small trials show improvements in reaction time, working memory, and fatigue reduction — including at low doses suggesting non-caffeine components contribute. Standardise by caffeine content to avoid over-dosing.

Dose: 50–200 mg guarana extract (delivering ~40–100 mg caffeine) 1–2 times daily