Equivalent Hypertrophy and Strength Gains in β-Hydroxy-β-Methylbutyrate- or Leucine-supplemented Men
Authors: Kevin T Murphy
Joshua K Vandeweerd
Chris McGlory
Josephine S Jakubowski
Kenneth S Noguchi
Stuart M Phillips
Robert W Morton
Everson A Nunes
Edwin P T Wong
Journal: Medicine and science in sports and exercise (2019)
Discipline: CLINICAL MEDICINE
Keywords: proteins; leucine; β-hydroxy, β-methylbutyrate (HMB); muscle hypertrophy; strength gains
Affiliations: Department of Kinesiology, McMaster University, Ontario, CANADA., Department of Physiological Sciences, Federal University of Santa Catarina, Florianopólis, BRAZIL.

Abstract:  Ingestion of proteins with high leucine content during resistance training (RT) can augment hypertrophy. Some data suggest that a leucine metabolite, β-hydroxy, β-methylbutyrate (HMB), is substantially more anabolically efficacious than leucine. Purpose: We aimed to test whether supplementation with HMB versus leucine, added to whey protein, would result in differential muscle hypertrophy and strength gains in young men performing RT. Methods: Twenty-six resistance-trained men (23 ± 2 yr) performed 12 wk of RT with three phases. Phase 1: 8 wk of periodized RT (three training sessions per week). Phase 2: 2 wk overreaching period (five sessions per week). Phase 3: 2 wk taper (three sessions per week). Participants were randomly assigned to twice daily ingestion of: whey protein (25 g) plus HMB (1.5 g) (whey+HMB; n = 13) or whey protein (25 g) plus leucine (1.5 g) (whey+leu; n = 13). Skeletal muscle biopsies were performed before and after RT. Measures of fat- and bone-free mass, vastus lateralis (VL) muscle thickness and muscle cross-sectional area (CSA) (both by ultrasound), muscle fiber CSA, and 1-repetition maximum (1-RM) strength tests were determined. Results: We observed increases in fat- and bone-free mass, VL muscle thickness, muscle CSA and fiber type CSA and 1-RM strength with no differences between groups at any phase. We observed no differences between groups or time-group interactions in hormone concentrations at any phase of the RT program. Conclusions: β-Hydroxy-β-methylbutyrate added to whey did not result in greater increases in any measure of muscle mass, strength, or hormonal concentration compared to leucine added to whey. Our results show that HMB is no more effective in stimulating RT-induced hypertrophy and strength gains than leucine. 

Retracted: No

PubPeer comments:
 Copy pasted from https: journals.lww.com acsm-msse Citation 2021 01000 Corrigendum.33.aspx (Medicine Science in Sports Exercise. 53(1):247, January 2021):  The authors of articles (1)u2013(4) below amend their conflict-of-interest statements to include the following: Dr. Stuart M. Phillips is listed as an inventor on patent (Canadian) 3052324 issued to Exerkine, and a patent (US) 16 182891 pending to Exerkine (but reports no financial gains). Dr. Phillips reports personal fees from Enhanced Recovery (donated to charity), equity from Exerkine (all proceeds donated to charity), outside the submitted work. See https: retractionwatch.com 2021 02 12 eleven-papers-corrected-after-nutrition-prof-fails-to-disclose-patent-company-ties for backgrounds. ,