b-hydroxy-b-methylbutyrate is a leucine metabolite studied for its anticatabolic effects and potential benefits on strength and muscle mass gains associated with resistance training. The aim of this review was to discuss the effects of b-hydroxy-b-methylbutyrate supplementation on strength and hypertrophy in previously trained or untrained young and older adults. Studies undertaken with individuals initiating a resistance training program have suggested that a daily b-hydroxy-b-methylbutyrate supplementation dosage of 1.5 to 3.0g may be responsive as an ergogenic aid up to the fourth or fifth week of resistance training. Such effects do not seem to remain afterward, when gains in strength and muscle mass are the result of resistance training only. In resistance trained subjects b-hydroxy-b-methylbutyrate supplementation did not show any additional benefits during resistance training. b-hydroxy-b-methylbutyrate supplementation has been shown to reduce total cholesterol and low-density lipoprotein cholesterol, although there seems to be no available recommendation for its supplementation, since scientific evidence is lacking. No b-hydroxy-b-methylbutyrate adverse effects have been observed, and its supplementation is apparently safe, however, most studies were conducted during a short-term period (less then 4 weeks) and with untrained individuals. There is a need for more studies to elucidate the physiological mechanisms underlying the anticatabolic action of b-hydroxy-b-methylbutyrate supplementation in untrained subjects, and to investigate possible adverse effects.
Diet; Hypertrophy; Dietary supplements
