Ingredient guide
Caffeine is the most widely used stimulant in the world. The evidence that it improves alertness and physical performance is strong. The key questions are dose, timing, and tolerance, with up to 400 mg per day considered safe for most non-pregnant adults.
High-quality evidenceCaffeine is a natural stimulant found in coffee, tea, cocoa, and guarana, and added to many energy and pre-workout products. In supplements it often appears as caffeine anhydrous, a dried, concentrated form. It is the most widely consumed active compound on the planet.
Caffeine blocks adenosine, a molecule that builds up through the day and makes you feel sleepy. By sitting in adenosine's parking spots, caffeine keeps drowsiness at bay and lets stimulating signals run more freely. That is why a dose lifts alertness and lowers the feeling of effort during a workout.
This is one of the few supplement ingredients with genuinely strong human evidence. Many controlled trials show that caffeine improves alertness, reaction time, and memory encoding, and that it raises endurance and some power and strength measures around exercise. The performance dose is well mapped, at roughly 3 mg to 6 mg per kilogram of body weight before activity.
The catch is not whether caffeine works but how you use it. A single dose lifts alertness for only an hour or two and can be followed by a slump. Regular use builds tolerance, and late doses harm sleep. We grade the evidence as high for alertness and performance, with the real skill being dose and timing.
Most people get caffeine from coffee and tea, which is fine. For a performance dose, the research points to 3 mg to 6 mg per kilogram about an hour before exercise. Keep your daily total under 400 mg, avoid late-day doses if sleep matters, and treat concentrated powders with respect. If you have a heart condition or take medication, check with your healthcare provider first.
For exercise, studies use about 3 mg to 6 mg per kilogram of body weight, roughly 200 mg to 400 mg for a 70 kg adult, taken around 60 minutes before. Up to 400 mg per day from all sources is considered safe for most non-pregnant adults. Pregnant people are usually advised to stay under 200 mg. Ask your healthcare provider if you are unsure.
Up to 400 mg per day from all sources is considered safe for most non-pregnant adults. In pregnancy the usual advice is to stay under 200 mg.
Studies generally use 3 to 6 mg per kilogram of body weight about 60 minutes before exercise. Start at the low end to gauge how you respond.
Regular use builds tolerance, so the same dose has less effect over time. A short break can return your sensitivity, though it may bring temporary withdrawal headaches.
They can be. Pure powders are so concentrated that a small measuring error can reach a harmful dose. Measured tablets or normal drinks are far safer.