HMB increases protein synthesis and reduces muscle damage caused by training.
When protein synthesis index is similar to protein degradation index, there is no significant increase in muscle mass. HMB contributes to muscle development in two ways: Increases protein synthesis and reduce protein breakage.
In a study published in the Journal of Applied Physiology, athletes who took supplementation with HMB had lower rates of proteolysis (protein degradation). In addition to this, they could also increase the load each week in lifting exercises they practiced. The HMB doses used during this study were 1,5 g and 3 g.
This test showed that HMB contributes to muscle growth improving muscle fibers development and avoiding protein degradation, which is very important for muscle growth.
However, this study is not a single case. In 2000, it was published a study about 39 men and 36 women to find out the effects of HMB supplementation in endurance training. Subjects were divided into two groups: the one with placebo and the one who took 3 g of HMB.
HMB stimulates protein synthesis, increases muscle mass and avoids catabolism: it changes the balance of protein synthesis tilting the scale in favor of muscle. When protein synthesis is the same as protein breakdown, there is no net income on muscle protein.
This is very important for the maintenance / strength increase ratio. HMB helps to increase muscle protein by two procedures:
– HMB decreases protein degradation caused by hard training in a molecular level by stopping proteolysis (the natural process of muscle tissue breakdown which is produced after an intense physical activity, as, for instance, the increase in loads or weights) through the proteolytic ubiquitin-proteasome system, the proteolytic enzyme that breaks down the muscle protein.
– HMB is the metabolite of leucine, a member of BCAA. It stimulates protein synthesis through mTOR / p70S6K system, a physiological process that gets a hormone signaling which stimulates the beginning of protein synthesis.