The Role of HMB Supplementation in Enhancing the Effects of Resistance Training in Older Adults: A Systematic Review and Meta-Analysis on Muscle Quality, Body Composition, and Physical Function.

RT+HMB produced borderline significant improvements in handgrip strength compared to RT alone in older adults.

• Pooled SMD for handgrip strength was 0.24 (95% CI 0.00–0.48; p = 0.05)
• The effect was described as 'modest and borderline significant'
• Ten trials with n = 596 participants met inclusion criteria
• Standardized mean differences with 95% confidence intervals were calculated using pooled estimates

RT+HMB produced moderate and statistically significant improvements in Short Physical Performance Battery (SPPB) scores compared to RT alone.

• Pooled SMD for SPPB scores was 0.54 (95% CI 0.12–0.95; p = 0.01)
• This was described as a 'moderate benefit' in overall physical function
• SPPB is a composite measure of physical function including balance, gait, and chair stand tests
• This was one of only two outcomes showing statistically significant effects

RT+HMB showed no significant effects on gait speed, appendicular lean mass, muscle quality, fat mass, or body weight compared to RT alone.

• All non-significant outcomes had p > 0.05
• Outcomes assessed included gait speed, appendicular lean mass, muscle quality (MQ), fat mass, and body weight
• No statistically significant improvements in body composition were observed
• Ten randomized controlled trials (n = 596) were included in the analysis

Half of the included trials were rated at high risk of bias, limiting confidence in the pooled estimates.

• Five of ten trials (50%) were rated at high risk of bias
• Risk of bias was assessed using Cochrane RoB 2 tool
• Methodological quality was also assessed with the PEDro scale
• The authors noted this limits 'confidence in pooled estimates'

The systematic review and meta-analysis identified ten eligible randomized controlled trials comparing RT+HMB with RT alone in older adults.

• Six databases were searched: PubMed, Scopus, Cochrane Library, CINAHL, Web of Science, and ScienceDirect, up to July 2025
• The review followed PRISMA guidelines and was registered with PROSPERO (CRD420251144810)
• Total pooled sample size across ten trials was n = 596 participants
• Inclusion criteria required randomized controlled trial design comparing RT+HMB with RT alone