Sci-Fit HMB (Beta-Hydroxy-Beta-Methylbutyrate) is found naturally in living matter as a metabolite of the essential amino acid L-leucine. There is preliminary evidence suggesting HMB may be an anticatabolic and immunomodulatory substance.

In one study of HMB, the supplemented subjects receiving 1.5 grams or 3 grams daily were able to lift more weight than the unsupplemented control group. The researchers concluded that either dose of HMB "can partly prevent exercise induced proteolysis and/or muscle damage and result in larger gains in muscle function associated with resistance training."

HMB has been shown in controlled studies (with athletes performing regular resistance training) that when taken at 3 grams per day, produce a 300% greater increase in lean mass gain.

HMB has a pronounced effect on decreasing the protein breakdown induced by resistance training along with increasing nitrogen retention by the body, resulting in a subsequent increase in lean muscle mass and strength.