Caffeine
- Effective dose
- 100–400 mg
- Evidence
- 5/5· Robust
Last updated June 1, 2026
What it is
Caffeine is a central nervous system stimulant and the most studied ergogenic aid in sport science. It blocks adenosine receptors, reducing perceived exertion and improving alertness.
Benefits
Improves endurance, power output, and time-to-exhaustion across a wide range of activities. Most reliable benefits at 3–6 mg per kg of body weight, taken 30–60 minutes before exercise.
When to take it
Take roughly 60 minutes before exercise. Avoid late-day dosing to protect sleep.
Side effects
Jitters, anxiety, elevated heart rate, GI upset, and disrupted sleep when taken late in the day. Tolerance develops with daily use.
Sources
Products containing Caffeine
No products in our database contain this ingredient yet.