Caffeine is the most evidence-backed ergogenic (performance-enhancing) aid. At 3-6mg per kg bodyweight, taken 30-60 minutes before exercise, it improves endurance, strength, power output, reaction time and focus by blocking adenosine receptors and reducing perceived exertion. Tolerance develops with regular use, so some athletes cycle their intake. Caffeine’s half-life (~5-6 hours) means afternoon and evening intake impairs sleep — which harms recovery more than the caffeine helps performance.
Key points
- Most effective legal ergogenic aid
- 3-6mg/kg, 30-60 min pre-exercise
- Improves endurance, strength, power, focus
- Avoid late-day use (impairs sleep)