Supplement
Caffeine (Performance Dose)
1 to 3 mg/kg before performance. Watch the sleep cutoff.
What it does
One of the most-studied and reliably effective performance enhancers. Strategic morning-to-early-afternoon use improves output; careless afternoon use degrades sleep architecture and builds a tolerance cycle.
Antagonizes adenosine receptors, blocking the daytime buildup of sleep pressure. Performance comes from this disinhibition of arousal plus secondary dopamine and norepinephrine effects.
What the evidence shows
Overall evidence strength: High certainty
Who it's for, who should skip
Before training or cognitive work, dosed for the task, with a hard cutoff well before bed. Subjective "I sleep fine after coffee" understates the architectural cost of late caffeine.
Running it
- Form
- oral
- Dose
- 1–3 mg/kg · as needed for performance windows · last dose ≥8 hr before intended sleep
- Cycling
- tolerance develops with daily use
Safety
- fragments sleep architecture with late dosing, even when sleep onset feels normal
Stacking & alternatives
Access & cost
Available over the counter.
Last reviewed 27 August 2026.