Fernández-Landa et al. 2024, HMB and endurance performance meta-analysis

A systematic review and meta-analysis of 11 RCTs (n = 279) found that HMB supplementation (3 g·d⁻¹ for 2–12 weeks) produced a statistically significant improvement in endurance performance and VO2max (SMD ≈ 0.58 for both outcomes), with the effect persisting after exclusion of higher-risk studies. The pooled sample was small and predominantly recreationally active rather than trained endurance athletes, so the size of any real-world benefit in competitive distance runners remains uncertain. Moderate evidence.