Caffeine helps CrossFit scores, but only a little

Caffeine is one of the most widely used performance aids in sport, but most of the evidence comes from single disciplines such as endurance events or straightforward strength tests. CrossFit is different: workouts mix heavy lifting, gymnastics movements and high-intensity conditioning in unpredictable combinations, so it is not obvious that caffeine's known benefits carry over. Athletes also want to know whether the dose, the delivery form or their training background changes the payoff. This review set out to pool everything tested so far in CrossFit specifically.

The authors systematically searched multiple electronic databases for randomised crossover studies, in which the same participants completed CrossFit performance tests with and without acute caffeine. Seven studies met the criteria, covering 103 participants, of whom just 13 were women. Performance effects were pooled in a three-level random-effects model, while physiological outcomes such as blood lactate were combined in conventional models. The team also compared effects by training status, recreationally active versus trained, and by delivery form, capsule versus beverage, and used meta-regression to test whether the relative caffeine dose predicted the size of the performance change.

Caffeine produced a small favourable effect on overall CrossFit performance, with a pooled Hedges' g of 0.13. Blood lactate concentrations were higher after caffeine, with a moderate pooled effect of 0.53. Stratified estimates favoured caffeine in recreationally active participants (0.20) and when it was taken in capsule form (0.17), yet formal tests found no significant differences between subgroups. The relative dose did not explain variation in performance effects in either a linear or a nonlinear model, so taking more did not clearly deliver more.

Caffeine's benefits are well documented across many sports, and this review extends that picture to mixed-modal CrossFit training, though with a notably smaller effect than gym folklore often suggests. The finding that dose did not track with performance sits alongside a wider debate about whether bigger caffeine doses buy bigger gains. The authors flag the small number of studies, the predominance of male participants and inconsistent CrossFit test protocols as reasons for caution. Larger trials with more women and standardised workouts are the obvious next step.

If you take caffeine before a CrossFit session, this evidence suggests you are probably getting a real but small edge, not a transformation of your scores. The higher blood lactate readings hint that caffeinated athletes may be able to push harder, though the review cannot confirm why. There is no sign here that a larger dose helps more, or that capsules meaningfully beat drinks once the comparison is made formally. Women in particular have little data to go on, so the effect in female athletes remains an open question.