Research · 3 min read · 2026-10-12
Does caffeine make you faster?
Caffeine improves endurance performance, typically at 3 to 6 mg per kg of body weight about an hour before. How to try it safely.
Coffee before a race is a habit for many runners. Caffeine is also one of the best studied aids to performance. How much does it help, and how much do you need?
What the researchers did
An umbrella review from 2020 collected 21 meta-analyses from 11 reviews of caffeine and exercise performance. A position stand from the International Society of Sports Nutrition in 2021 summarised the research on dose, timing and individual differences.
What they found
Caffeine improved performance across many types of exercise. The effect tended to be larger for endurance than for short, intense efforts, and endurance was the type of exercise with the most consistent benefit.
A dose of 3 to 6 mg per kg of body weight consistently improved performance, and lower doses down to about 2 mg per kg may work too. It was most often taken about an hour before exercise. Caffeine gum may work faster, and gels with caffeine also improved performance.
People responded differently. Some had poor sleep or felt anxious, and how much caffeine you normally take may also play a part.
What it means for you
For a 70 kg runner, 3 mg per kg is about 210 mg. Start at the low end. More is not necessarily better, and side effects increase with the dose.
Try it before a long run or a hard session first, never for the first time on race day. For a late race or an evening session, think about your sleep afterwards. If you are pregnant or have a heart condition, ask your doctor first.
What the research can't tell you
Most studies included young men. Effects in women and older runners are less studied, and the quality of the evidence was mostly rated moderate.
How we use it
PX7 Training doesn't recommend supplements. If you use caffeine before a race, practise it before your long runs or key sessions so you know how you react.
Sources
- Grgic et al. (2020), Wake up and smell the coffee: caffeine supplementation and exercise performance, an umbrella review of 21 published meta-analyses. British Journal of Sports Medicine.
- Guest et al. (2021), International Society of Sports Nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition.
Written by Jørgen Larsen for PX7 Training.