Skeletal muscle protein turnover was measured in healthy young men in response to an oral dose of either 2.4 g of HMB in free acid form or 3.4 g of leucine. While both HMB and leucine stimulated muscle protein synthesis, HMB was also shown to attenuate muscle protein breakdown (-57%). The authors concluded that HMB induces anabolic effects in skeletal muscle that are distinct and/or additive to the effects of leucine.