HMB for Sports & Fitness
HMB (beta hydroxy-beta-methylbutyrate) is a metabolite of the essential amino acid leucine (one of the branched-chain amino acids).
Why Do Athletes Use It?*
Some athletes say that HMB promotes the loss body fat, helps build muscle and increase strength, speeds recovery between workouts, and reduces post-workout soreness.
What Do the Advocates Say?*
HMB may assist in accelerating the loss of body fat.
Exercise-induced muscle protein breakdown appears to decrease with HMB supplementation. This, in turn, should speed up recovery from exercise-induced muscle damage.
Enhanced strength and increased muscle mass have been documented in people supplementing with HMB. However, to date, a very limited number of studies have been done. Longitudinal studies to indicate possible long-term use effects of HMB have not been completed.
How Much Is Usually Taken by Athletes?
Biochemical and animal research shows HMB has a role in protein synthesis and might improve muscle growth and overall body composition as a supplement. However, double-blind human research suggests that HMB may only be effective when combined with an exercise program in people who are not already highly trained athletes. Double-blind trials found no effect of 3 to 6 grams per day HMB on body weight, body fat, or overall body composition in weight-training football players or other trained athletes.1,2,3,4,5 However, one double-blind study found that 3 grams per day HMB increased the amount of body fat lost by 70-year old adults who were participating in a strength-training program for the first time.6 A double-blind study of young men with no strength-training experience reported greater improvements in muscle mass (but not in percentage body fat) when HMB was used in the amount of 17 mg per pound of body weight.7 However, another group of men in the same study given twice as much HMB did not experience any changes in body composition.