How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Caffeine
One of the most studied stimulants in the world: alertness, endurance, and reduced perception of effort during training.
Benefits
- Improves aerobic endurance, strength, muscular endurance, power, and speed, with the clearest effect in endurance (review of 21 meta-analyses)
- Increases movement velocity in weight training, with light, medium, or heavy loads (meta-analysis)
- In ball sports, improves sprinting in 80% of studies and vertical jump in 88%, at 3 to 6 mg per kilo
- Over 2,000 m of rowing, 6 mg per kilo made the race about 2% faster
Precautions
Can cause nervousness, palpitations, and sleep disorders. To be avoided late in the day. Caution in case of hypertension, heart conditions, anxiety, or pregnancy.
Recommended dosage
3 to 6 mg per kilo of body weight, about 60 minutes before exercise.
How to take it
- Dose: 3 to 6 mg per kilo of body weight. Around 3 mg/kg, the gain is kept with the fewest side effects; from 6 mg/kg, palpitations and sleep disorders become more frequent.
- When: about 60 minutes before exercise, the timeframe adopted by the International Society of Sports Nutrition position stand.
- If you already drink coffee: it does not cancel the effect. Cyclists who were low, moderate, or high consumers gained just as much with 6 mg/kg.
- Not necessarily in a capsule: in the form of chewing gum, 3 mg/kg improved a time trial by 3 to 4%.
- And your sleep: sleep disorders are one of the two most frequent side effects in athletes, along with palpitations.
- Not everyone responds the same way: genetics (the CYP1A2 gene) modulates the effect, but studies do not yet allow for practical advice to be drawn from it.
Did you know?
A habitually high intake of caffeine does not appear to negate the benefits of acute caffeine supplementation on endurance performance.
What the studies say
This systematic review and meta-analysis examined the effects of acute caffeine supplementation on movement velocity during resistance exercise. It concluded that caffeine is highly ergogenic, significantly improving both mean and peak movement velocities. These benefits were observed for light, moderate, and heavy loads, as well as for lower and upper body exercises.
Raya-González J, Rendo-Urteaga T, Domínguez R, Castillo D, Rodríguez-Fernández A, Grgic J. — Sports medicine (Auckland, N.Z.) (2020) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more