What is it?

β-Hydroxy β-methylbutyrate (HMB) is a compound that is linked to the prevention of  muscle breakdown. It is a metabolite of the amino acid, leucine. Leucine is metabolized into alpha-ketoisocaproate, which is then turned into HMB.

What does it do?

Researchers are not completely sure how HMB works in the body. The exact mechanism behind HMB’s effectiveness will have to be determined in future research. Although researchers are not certain of the mechanisms of HMB, the results behind HMB are positive. This amino acid metabolite minimizes protein breakdown due to high intensity workouts. HMB decreases body fat and increases muscle mass in untrained individuals beginning to workout. It also slows the loss of muscle in cancer and aids patients.

HMB is a chemical that occurs naturally in the body when the amino acid, leucine, breaks down. HMB is found in grapefruits, catfish and plants such as alfalfa and corn silage.

Studies have been conducted using HMB as a supplement, and has had two different types of effects. A study conducted on a NCAA football team of trained athletes produced no results while taking HMB (Hoffman et al). Body Builders who have taken HMB have not benefited from this supplement either. The individuals who have benefited from this study are untrained athletes, cancer, and aids patients. This is not a cure for cancer or aids patients, but the supplement prolongs the breakdown of these patients muscles. In another study, HMB helps in reducing muscle loss in the elderly (Vukovich et al). This supplement is marketed to body builders, but is more beneficial in the medical community.

HMB seems to be safe when taken at standard doses. Clinical trials have not found any significant adverse effects with the short-term use of HMB. Both short and long-term toxicological studies in animals have also found no evidence of harm. HMB has never been tested on pregnant woman.