Effects of β-Hydroxy-β-Methylbutyrate Supplementation During Resistance Training on Strength, Body Composition, and Muscle Damage in Trained and Untrained Young Men: A Meta-Analysis

Abstract

Beta-hydroxy-beta-methylbutyrate (HMB) is a popular supplement in the resistance training community, with its use supported by claims of increased strength, muscle growth, and improved recovery; however, research outcomes are variable. Therefore, we meta-analyzed the effectiveness of HMB on strength, body composition, and muscle damage. Nine qualifying studies yielded 14 comparisons subcategorized by training experience (trained, untrained) to provide 12-13 estimates of strength (upper body, lower body, overall average), 13 estimates of fat and fat-free mass, and 7 estimates of the muscle-damage marker creatine kinase. The meta-analysis comprised 394 subjects (age 23 +/- 2 years, mean +/- between-study SD) with 5 +/- 2 weeks' intervention and 5 +/- 6 h.wk of training. The estimates were analyzed using a meta-analytic mixed model with study sample size as the weighting factor that included the main-effect covariates to control for between-study differences in HMB dose, intervention duration, training load, and dietary cointervention. To interpret magnitudes, meta-analyzed effects were standardized using the composite baseline between-subject SD and were qualified using modified Cohen effect size thresholds. There were small benefits to lower-body (mean +/- 90% confidence limit: 9.9% +/- 5.9%) and average strength (6.6 +/- 5.7%), but only negligible gains for upper-body strength (2.1 +/- 5.5%) were observed in untrained lifters. In trained lifters, all strength outcomes were trivial. Combined (all studies), the overall average strength increase was trivial (3.7 +/- 2.4%), although uncertainty allows for a small benefit. Effects on fat and fat-free mass were trivial, and results regarding creatine kinase were unclear. Supplementation with HMB during resistance training incurs small but clear overall and leg strength gains in previously untrained men, but effects in trained lifters are trivial. The HMB effect on body composition is inconsequential. An explanation for strength gains in previously untrained lifters requires further research.

Resistance training & beta-hydroxy-beta-methylbutyrate supplementation on hormones

“…It has been suggested that the HMB effect on body composition is inconsequential 23 .Some studies reported that HMB was unable to change the body composition of athletes involved in resistance training (22), water polo, rowing 9 or football 17,24 .On the other hand, a number of studies failed to confirm these results and indicated that HMB supplementation during 2-to 12-weeks of training promoted significantly greater changes in FFM and fat loss in trained and untrained men and women 4,5,25,26 . Based on previous studies, the data about the effect of HMB supplementation on body composition is inconsistent.…”

Effects of β-Hydroxy-β-Methylbutyrate Supplementation on IL-4, IL-10 and TGF-β1 during Resistance Exercise in Athletes

“…β-Hydroxy-β-methylbutyrate (HMB) is a metabolite of the amino acid leucine that has previously been shown to increase protein synthesis, strength and power, and decrease circulating markers of muscle damage [19]. To date, three studies only have been evaluated the effect of HMB on immune function during RE in humans [6,17,18].…”

Scientific Opinion on the substantiation of health claims related to β-hydroxy β-methylbutyrate monohydrate (HMB) alone or in combination with α-ketoisocaproic acid (KIC) and reduction of muscle tissue damage during exercise (ID 1577, 1584), increase in l

“…This meta-analysis included only seven RCTs on HMB (and 9 intervention arms), all of which were included in the meta-analysis by Rowlands and Thomson (2009). The Panel considers that this meta-analysis does not provide evidence for the scientific substantiation of the claims in addition to that of the meta-analysis by Rowlands and Thomson (2009).…”

“…In the meta-analysis by Rowlands and Thomson (2009), a total of five studies, including eight effect estimates, addressed the effects of HMB supplementation on muscle damage during resistance training by means of blood concentrations of CK as a marker of muscle membrane damage (Jówko et al, 2001;Kreider et al, 1999;Kreider et al, 2000;Nissen et al, 1996;Panton et al, 2000). All intervention arms used doses of HMB of 3.0 g/day except one (i.e.…”

“…Ten of the 11 RCTs considered in the meta-analysis by Rowlands and Thomson (2009), and which included 16 intervention arms, assessed the effects of HMB supplementation on lean body mass and reported size estimates. Body composition was assessed by skin fold thickness in three trials (Gallagher et al, 2000;Panton et al, 2000;Ransone et al, 2003), by bioelectrical impedance analysis (BIA) in two trials (Jówko et al, 2001;Thomson et al, 2009), by total body electrical conductivity (TOBEC) in one trial (Nissen et al, 1996), and by dual-energy x-ray absorptiometry (DXA) in four trials (Kreider et al, 1999;Kreider et al, 2000;Slater et al, 2001;.…”