Mixed
Caffeine supplementation at low-to-moderate dosages (3-6 mg/kg) significantly enhances sport performance, particularly in endurance and high-intensity team sports, whereas higher dosages (≥9 mg/kg) do not provide further enhancement and may be counterproductive.
If you are a trained athlete, take 3-6 mg of caffeine per kg of body weight about an hour before your event. Do not exceed this range, as higher doses offer no extra benefit and may hurt your performance. Anhydrous caffeine (capsules/powder) is more effective than coffee, but coffee is still better than nothing if you prefer it.
Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg).
Why this rating
This is a Position Stand from the International Society of Sports Nutrition, synthesizing extensive literature.
Source
International society of sports nutrition position stand: caffeine and performance
Erica R. Goldstein et al. · Journal of the International Society of Sports Nutrition · 2010
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