Effect of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis

The purpose of this study was to quantify which dietary supplements augment lean mass and strength gains during resistance training. Peer‐reviewed studies between the years 1967 and 2001 were included in the analysis if they met a predetermined set of experimental criteria, among which were at least 3‐week duration and resistance training two or more times a week. Lean mass and strength were normalized for meta‐analysis by conversion to percent change per week and by calculating the effect size for each variable. Of the 250 supplements examined, only six had more than two studies that met the criteria for inclusion in the meta‐analysis. Creatine and β‐hydroxy‐beta‐methylbutyrate (HMB) were found to significantly increase net lean mass gains of 0.36%/week and 0.28%/week and strength gains of 1.09%/week and 1.40%/week (P