How long before a race should I take caffeine?

Take caffeine 30 to 60 minutes before the start of your race to hit peak blood concentration at the gun. Caffeine reaches maximum plasma levels around 45 to 60 minutes after ingestion, so timing your dose for 45 minutes pre-start is a solid default for most athletes. If you are using caffeine gel or chews that absorb slightly faster than capsules, 30 to 40 minutes is fine. For very long events (ultra-distance or full Ironman), consider splitting your dose: a moderate amount pre-race and additional caffeine mid-race when fatigue builds. Do not experiment with new timing or new products on race day.