There is some evidence that HMB can have an anti-catabolic effect by inhibiting protein breakdown. This study combined HMB with two amino acids
that have been shown to stimulate protein synthesis. The combination was hypothesized to blunt the gradual loss of muscle that occurs in the elderly. Elderly women were randomly assigned to a placebo group or a HMB (2 g/day), arginine
(5 g/day), and lysine
(1.5 g/day) group for 12 weeks. The active supplement group demonstrated increased protein synthesis, lean body mass, leg strength and improvement in the activities of daily living compared to placebo. It is unclear if the amino acids, the HMB, or the combination was responsible for the effects but the data indicate a favorable effect of the combination of HMB, lysine, and arginine for the elderly.
Flakoll P, Sharp R, Baier S, Levenhagen D, Carr C, Nissen S. Effect of beta-hydroxy-beta-methylbutyrate, arginine, and lysine supplementation on strength, functionality, body composition, and protein metabolism in elderly women. Nutrition. 2004 May;20(5):445-51.