Caffeine

Caffeine: The Dose, and the Sleep Cost

The best-evidenced performance supplement there is, with a side effect that quietly undoes the training it was meant to improve.

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3–6 mg per kg before training. Count every source, and keep it far enough from bedtime that it does not cost you the sleep your recovery depends on.

The dose is per kilogram for a reason

The studied performance range is roughly 3–6 mg per kilogram of bodyweight taken half an hour to an hour before exercise. For a 60 kg athlete that is about 180–360 mg; for a 100 kg athlete, 300–600 mg. A fixed 300 mg scoop is a very different drug across those two people.

Benefits appear across endurance, strength and repeated-sprint work, and caffeine is one of the few ergogenic aids where the effect is large enough to notice without instrumentation.

Higher is not better past this range. Above it, side effects climb — jitteriness, elevated heart rate, gastrointestinal upset, anxiety — while performance does not.

Count every source

Panels list caffeine anhydrous separately from botanical sources such as green tea extract, guarana and yerba mate, each of which contributes caffeine of its own. A product's headline number can therefore understate its total.

Add coffee, tea, energy drinks, pre-workout and any thermogenic in the same day. People who feel wired on a 'moderate' pre-workout are frequently at double the dose they think.

Tolerance, and the part that matters most

Tolerance develops to some effects, notably the subjective stimulation, more readily than to others. The common response — escalating the dose — raises side effects faster than benefit. Periodically reducing intake restores sensitivity.

The more important point is sleep. With a half-life of about five hours, a 300 mg afternoon dose can leave a substantial amount circulating at bedtime, and individual clearance varies widely with CYP1A2 activity. Caffeine measurably degrades sleep quality in people who report no trouble falling asleep.

Sleep is doing more for strength, recovery and body composition than any supplement on this site. A pre-workout that improves one evening session while costing an hour of sleep quality is a bad trade, and it is the most common unforced error in this category.