HMB (Beta-Hydroxy-Beta-Methylbutyrate)

HMB is a metabolite of the amino acid leucine. In clinical studies, leucine and one of its metabolites, KIC (alphaketoisocaproate acid), have been shown to have a stabilizing effect on the integrity of cell membranes. These clinical studies focused on muscle cell membrane stability. KIC and leucine have been used in several studies, which explored their enhancing effect on athletic activity. Unfortunately, very high doses are often required. Supplementation with leucine would require about 60 grams per day to have a therapeutic effect, which is the amount of leucine contained in four to six pounds of red meat. Obviously, it would be ineffective to try to consume that much meat in order to ingest adequate leucine.

HMB, a downstream metabolic metabolite of the amino acid leucine, seems to work at the cellular level by stabilizing cell membranes and (possibly through accentuation of various cellular repair processes within the cell) to make the cell more adaptable to stress. For this reason, it has been used significantly in athletic circles as a muscle and strength building aid, in addition to an adjunct to weight loss. As a matter of fact, in clinical studies where athletes were given three grams of HMB daily, all experienced a significant increase in muscle mass and subsequent decrease in body fat.

In addition, there was a tendency toward normalization of cholesterol levels. It is possible that HMB may actually decrease cholesterol levels in the body and slightly increase HDL levels. HDL is considered a good type of cholesterol.

HMB seems to have utility in specific medical applications. It has been used as an anti-cachexia agent in adjunctive treatment for cancer patients. It seems to have a stabilizing effect in the prevention of excessive weight loss and stabilization of the overall health of the body's cells and muscle mass. It is also applicable for certain types of serious infections, such as hepatitis. Currently, there are trials being conducted, which study the efficacy in the treatment of HIV-related disease. Anecdotally, it seems to be helpful in those with congestive heart failure, as it has a stabilizing effect on the heart muscle itself, thereby likely improving the heart's efficiency.

Most studies with HMB utilize a three-gram dose, given in three separate doses throughout the day. However, by anecdotal report, higher doses have been used, especially in larger individuals, who have shown a very good response. The safety profile of HMB is very good, with studies giving as much as 100 grams daily showing no adverse effects. As to side effects with the use of HMB in my clinical practice, one case of constipation was reported. Presumably, this was related to the calcium component of HMB. Otherwise, I have noted no particular problems with long-term HMB consumption.

If you have any questions, please contact the Advanced Medical Center.

Dale Guyer, M.D.