??-Hydroxy-F128b-Methylbutyrate (HMB) Supplementation and the Promotion of Muscle Growth and Strength

Abstract

Beta-hydroxy beta-methylbutyrate (HMB), a metabolite of the essential amino acid leucine, is one of the latest dietary supplements promoted to enhance gains in strength and lean body mass associated with resistance training. Unlike anabolic hormones that induce muscle hypertrophy by increasing muscle protein synthesis, HMB is claimed to influence strength and lean body mass by acting as an anticatabolic agent, minimising protein breakdown and damage to cells that may occur with intense exercise. Research on HMB has recently tested this hypothesis, under the assumption that it may be the active compound associated with the anticatabolic effects of leucine and its metabolites. While much of the available literature is preliminary in nature and not without methodological concern, there is support for the claims made regarding HMB supplementation, at least in young, previously untrained individuals. A mechanism by which this may occur is unknown, but research undertaken to date suggests there may be a reduction in skeletal muscle damage, although this has not been assessed directly. The response of resistance trained and older individuals to HMB administration is less clear. While the results of research conducted to date appear encouraging, caution must be taken when interpreting outcomes as most manuscripts are presented in abstract form only, not having to withstand the rigors of peer review. Of the literature reviewed relating to HMB administration during resistance training, only 2 papers are full manuscripts appearing in peer reviewed journals. The remaining 8 papers are published as abstracts only, making it difficult to critically review the research. There is clearly a need for more tightly controlled, longer duration studies to verify if HMB enhances strength and muscular hypertrophy development associated with resistance training across a range of groups, including resistance trained individuals.

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

“…Leucine and its metabolite keto--isocaproate (KIC) appear to inhibit protein degradation and this anti-proteolytic effect is believed to be mediated by HMB. HMB exerts its effects through protective anti-catabolic mechanisms and has been shown to directly influence protein synthesis 10,11 . In fact, HMB supplementation may affect cellular receptors and hormones, such as cortisol and testosterone, or the modulation of enzymes responsible for muscle catabolism 10 .…”

“…HMB exerts its effects through protective anti-catabolic mechanisms and has been shown to directly influence protein synthesis 10,11 . In fact, HMB supplementation may affect cellular receptors and hormones, such as cortisol and testosterone, or the modulation of enzymes responsible for muscle catabolism 10 . However, recent studies have generated a more concrete basis regarding HMB mechanisms of action 12 .…”

Competitive Edge: Review of the Role of Glutamine, Arginine and β -Hydroxy- β -Methylbutyrate Supplements for Enhancing Athletic Performance in Addition to Benefiting the Body During Times of Stress, Illness and Wound Healing

“…Cancer Tumor→Proteolysis-Inducing Factor (PIF)→Cancer-Related Skeletal Muscle Loss May et al [18] studied the effect of using oral supplementation of glutamine, arginine and HMB on cancer-related wasting syndrome. They conducted a randomized, double-blind, placebo-controlled study of 49 patients with advanced cancer (stage IV solid tumors).…”

“…During athletic training, damage to the muscles results in the breakdown of leucine as well as increased HMB levels. Evidence suggests that taking HMB supplements might facilitate the body to slow down the destruction of muscle tissue [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Therefore, HMB has been studied as a sports performance supplement for enhancing strength and muscle mass.…”

“…Therefore, HMB has been studied as a sports performance supplement for enhancing strength and muscle mass. The research is promising but contradictory and limited to small studies [18,[20][21][22][23][24][25][30][31][32][33][34][35]. Some studies of small double-blind trials have been negative [30,35].…”