The Effects of Beta-Hydroxy-Beta-Methylbutyrate Supplementation on Recovery Following Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 29676656 · doi:10.1080/07315724.2018.1451789
What was done
A systematic review and meta-analysis of randomized controlled trials searched Medline, Scopus, Cochrane Library, and Google Scholar through October 2017. The authors evaluated the effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation on indirect markers of exercise-induced muscle damage—specifically follow-up serum creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations—among healthy participants. Pooled effect sizes were calculated as weighted mean differences (WMD), with subgroup analysis by intervention duration (< 6 weeks vs. ≥ 6 weeks).
What was found
HMB supplementation significantly decreased indirect markers of muscle damage: - Creatine kinase (10 studies, n = 324): WMD = -60.71 U/L (95% CI, -78.12 to -43.29; I² = 4.1%, p-heterogeneity = 0.40). - Lactate dehydrogenase (8 studies, n = 229): WMD = -15.42 U/L (95% CI, -22.2 to -8.6; I² = 0.0%, p-heterogeneity = 0.53). - Subgroup analysis showed the effect was statistically significant in studies lasting ≥ 6 weeks (p < 0.001).
Why it matters
This review pools randomized trials to show that HMB consistently reduces circulating biomarkers of muscle breakdown following damaging exercise, with benefits most pronounced with longer-term supplementation.
Limits
The total sample size was small across included trials (324 participants for CK and 229 for LDH). The review measured only surrogate serum biomarkers rather than direct functional recovery metrics (e.g., muscle strength, soreness, or performance). Specific details regarding HMB dosing protocols, timing, participant training status, and exercise types are not reported in the abstract.