Met-Rx Hardcore HMB is a metabolite of the essential amino acid leucine. As with other amino acid related substances, HMB appears to play a role in the synthesis of protein - particularly the protein that builds new muscle. Research suggests that HMB may improve the growth of lean muscle tissue.

One study involving 28 individuals undergoing a regular weight training programme found that supplementing with 3g of HMB per day compared to no supplementation, contributed to greater gains of muscle over a 7 week period. Studies also show that HMB lowers both total and LDL cholesterol (‘bad‘ cholesterol) while increasing ‘good‘ HDL cholesterol.

These effects were noted in individuals taking no exercise, however in those taking regular exercise the effects were much greater.