Safety of beta-alanine supplementation in humans: a narrative review

Carnosine levels play a significant role in intracellular pH buffering during exercise. The limiting factor for muscle carnosine synthesis is the availability of beta-alanine. Results from meta-analysis showed a significant positive effect of beta-alanine supplementation on high-intensity exercise performance. Nonetheless, much less has been described about the safety of beta-alanine. The available literature indicates no adverse events related to beta-alanine usage; side effects such as paresthesia may be observed if a large single high dose of beta-alanine is taken, but the symptom can be attenuated either by using splitting doses (< 1.6 g) or a sustained-release formula. No adverse effects have been reported up to 24 weeks of beta-alanine supplementation (3.2 g.day(-1)), but the adverse effects of longer supplementation periods are still unknown. Most of the existing clinical studies were not designed with safety evaluations as primary end points. beta-Alanine is currently considered to be safe in healthy populations, at recommended doses, by the International Society of Sports Nutrition stands position, while the Australian Institute of Sports has established beta-alanine as a safe performance-enhancing supplement with strong scientific evidence (grade A). Cohort studies are needed evaluating the safety of beta-alanine among representative populations, and the effects of co-variables such as sex, age, and ethnicity.