British Journal of Nutrition

Full Papers

Human and Clinical Nutrition

β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men

Jacob M. Wilsona1 c1, Ryan P. Lowerya1, Jordan M. Joya1, Joe A. Waltersa1, Shawn M. Baiera2, John C. Fuller Jra2, Jeffrey R. Stouta3, Layne E. Nortona1a4, Eric M. Sikorskia5, Stephanie M. C. Wilsona6, Nevine M. Duncana1, Nelo E. Zanchia1 and John Rathmachera2a7

a1 Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL 33606, USA

a2 Metabolic Technologies, Inc., Iowa State University Research Park, Ames, IA, USA

a3 Sport and Exercise Science, College of Education, University of Central Florida, Orlando, FL, USA

a4 Biolayne, Inc., Tampa, FL, USA

a5 Department of Biology, University of Tampa, Tampa, FL, USA

a6 Department of Nutrition, IMG Performance Institute, IMG Academy, Bradenton, FL, USA

a7 Department of Animal Science, Iowa State University, Ames, IA, USA


The purpose of the present study was to determine the effects of short-term supplementation with the free acid form of β-hydroxy-β-methylbutyrate (HMB-FA) on indices of muscle damage, protein breakdown, recovery and hormone status following a high-volume resistance training session in trained athletes. A total of twenty resistance-trained males were recruited to participate in a high-volume resistance training session centred on full squats, bench presses and dead lifts. Subjects were randomly assigned to receive either 3 g/d of HMB-FA or a placebo. Immediately before the exercise session and 48 h post-exercise, serum creatine kinase (CK), urinary 3-methylhistadine (3-MH), testosterone, cortisol and perceived recovery status (PRS) scale measurements were taken. The results showed that CK increased to a greater extent in the placebo (329 %) than in the HMB-FA group (104 %) (P= 0·004, d= 1·6). There was also a significant change for PRS, which decreased to a greater extent in the placebo (9·1 (sem 0·4) to 4·6 (sem 0·5)) than in the HMB-FA group (9·1 (sem 0·3) to 6·3 (sem 0·3)) (P= 0·005, d= − 0·48). Muscle protein breakdown, measured by 3-MH analysis, numerically decreased with HMB-FA supplementation and approached significance (P= 0·08, d= 0·12). There were no acute changes in plasma total or free testosterone, cortisol or C-reactive protein. In conclusion, these results suggest that an HMB-FA supplement given to trained athletes before exercise can blunt increases in muscle damage and prevent declines in perceived readiness to train following a high-volume, muscle-damaging resistance-training session.

(Received August 17 2012)

(Revised October 19 2012)

(Accepted October 29 2012)

(Online publication January 03 2013)

Key Words:

  • β-Hydroxy-β-methylbutyrate free acid;
  • Muscle damage;
  • Recovery;
  • Hormones


c1 Corresponding author: J. M. Wilson, email


  Abbreviations: 3-MH, 3-methylhistadine; CK, creatine kinase; CRP, C-reactive protein; HMB, β-hydroxy-β-methylbutyrate; HMB-Ca, calcium β-hydroxy-β-methylbutyrate; HMB-FA, β-hydroxy-β-methylbutyrate free acid; PRS, perceived recovery status