Caffeine
Caffeine increases alertness, focus and endurance. It is the most researched ergogenic supplement in the world.
What the research shows
Shown repeatedly in humans, in reviews or meta-analyses.
The umbrella review by Grgic (2020) pools 21 meta-analyses and finds caffeine ergogenic for aerobic endurance, muscle strength, muscle endurance, power, jumping and speed, with GRADE quality rated moderate in most cases. The two ISSN position stands (2010 and 2021) reach the same picture, although the 2021 panel includes authors who sit on advisory boards of supplement brands. Most of the underlying trials were run in young men, so the picture for women and older people is less sharp.
Who it makes sense for: Almost anyone who trains hard or competes, at 3 to 6 mg per kilo of body weight about an hour beforehand. Skip it within six hours of bedtime, during pregnancy, with heart rhythm problems or untreated high blood pressure, and if it leaves you restless or jittery. Above 400 mg a day it is mostly side effects that get added.
How we weigh evidenceClinical dosage
Origin
Natural & syntheticNaturally found in coffee beans, tea leaves, cacao beans, and guarana. In supplements often synthetic (caffeine anhydrous) or extracted from green tea.
Safety
Up to 400mg of caffeine per day is considered safe for healthy adults (EFSA). Side effects like palpitations and insomnia mainly occur at higher doses or in sensitive individuals.
For comparison
A cup of coffee contains 80-100mg of caffeine. A pre-workout with 200mg caffeine is comparable to 2 cups of coffee. A can of cola contains only 35mg.
Dosage by weight and gender
The effective caffeine dose for sports performance is 3-6mg per kg body weight (Goldstein et al., 2010). For someone weighing 70kg that's 210-420mg, for 90kg it's 270-540mg. Women metabolize caffeine slightly slower on average, so a lower dose (3-4mg/kg) is a good starting point. During pregnancy, max 200mg per day (EFSA).
Frequently asked questions
How much caffeine per day is safe?
The EFSA considers 400mg per day safe for healthy adults. That's comparable to 4-5 cups of coffee. For pregnant women the maximum is 200mg per day.
Is caffeine in pre-workout dangerous?
No, as long as you stick to the recommended dose. Most pre-workouts contain 150-300mg of caffeine, which is within safe limits. Just watch that you don't also drink lots of coffee or energy drinks the same day.
When should I take caffeine before exercise?
Caffeine peaks 30-60 minutes after ingestion (Guest et al., 2021). Take your pre-workout 30-45 minutes before training. Avoid caffeine after 2 PM if you have trouble sleeping at night.
Scientific sources
The clinical dosages on this page are based on peer-reviewed research.
- International society of sports nutrition position stand: caffeine and performanceGoldstein ER et al. (2010)
- International society of sports nutrition position stand: caffeine and exercise performanceGuest NS et al. (2021)Funded by: Meerdere auteurs zitten in wetenschappelijke adviesraden van supplementenmerken; de ISSN verklaart geld te ontvangen van bedrijven die cafeïneproducten verkopen.
- Wake up and smell the coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analysesGrgic J et al. (2020)Funded by: Auteurs verklaren geen belangenverstrengeling.
Pre-workouts with Caffeine
5% Nutrition 5150
2 flavors
Hardcore pre-workout with 400mg caffeine from multiple sources, 4g citrulline, and 2.5g beta-alanine. Not for beginners — one of the strongest pre-workouts on the market.
JNX Sports Shadow-X
Thermogenic pre-workout from JNX Sports with 200mg caffeine, 2g citrulline, and 2g beta-alanine. Focus on energy and concentration.
Cellucor C4 Ultimate
Premium C4 with 300mg caffeine, 6g citrulline malate, 3.2g beta-alanine, and 3g creatine. Fully clinically dosed — top of the C4 line.
BSN N.O.-Xplode
3 flavors
Legendary pre-workout from BSN with 6g citrulline, 3g creatine, and 200mg caffeine. Popular for years with a complete formula for energy and pump.
Zumub Pre-Workout 300
Affordable pre-workout from Zumub with 3g creatine, 2g beta-alanine, and 200mg caffeine. Ideal entry-level option with a proven formula.
JNX Sports The Curse!
3 flavors
Compact pre-workout with small serving size (5g). 155mg caffeine, 1.6g beta-alanine, and creatine. Known for intense focus but low dosages.
Cellucor C4 Ripped
2 flavors
C4 variant for the cutting phase with L-Carnitine and CLA. Less caffeine (150mg), no creatine — focused on fat burning.
We keep the dosages and values on this page as accurate as possible based on selected studies. New research may change these values. Nothing on this page is medical advice. If you have any doubts, always consult a doctor.