The relevance of leucine to bodybuilders has been known for over 30 years. However, the discovery and isolation of active downstream metabolites of leucine
such as HMB has caused interest in this incredible amino acid to wane. This is unfortunate for bodybuilders as leucine provides much more than just the action
of a terminal metabolite. So there are mans reasons for bodybuilders to supplement with leucine.
Even if you're already taking HMB. Leucine is one of the three branched-chain amino acids (BCAA's), the others being valine and isoleucine. BCAA's are unique in that their metabolic fate ensures they'll be used primarily for muscle-protein synthesis. BCAA's are not metabolized by the liver instead, they're reserved for use by muscle tissue.
Leucine is cm essential amino acid: It cannot he synthesized by the body and must always be acquired from dietary sources. Leucine is available in larger concentrations in meat and dairy products, especially whey protein, and to a lesser degree in wheat germ, brown rice, soybeans, almonds, cashews brazil nuts, chickpeas, lentils and Corn, This amino stands out in its role in regulating protein synthesis and protein breakdown, Leucine also stimulates protein-synthesis in muscles promotes the healing of hones skin and muscle tissue: and helps stimulate synthesis of the anabolic and protein-sparing amino acid glutamine. Leucine is superior to the other BCAA's in eliciting a sustained insulin response. It creates a sustained insulin release which allows for a greater insulin-generated anabolic drive.
One end product of leucine metabolism is HMB (beta-hydroxymethlhutyrate), HMB has been actively studied and has been shown to duplicate some of the anabolic effects of leucine. In fact HMB has been credited for much of leucine's anabolic and anti-catabolic effects. However it's important to consider that leucine itself, along with each metabolite leading to the production of HMB, plays its own unique role in the body. It may be that the ratio of the individual leucine metabolites is important for an optimal outcome.
Does this mean you should supplement with leucine instead of HMB? This depends on many factors one of which is how much money you're willing to spend oil supplements. Leucine is less expensive than HMB, and if offers additional benefits not seen with HMB, However if you take leucine alone, you'll end up with less HMB than if you supplemented. You might consider reducing your dosage of HMB it you are supplementing with leucine. The normal dosage of HMB would be three grams per day so it you're taking leucine, you might drop your HMB dosage to 1 1/2 grams per day.
In supplement form a 200-pound bodybuilder should take two to four grams of leucine before training, postworkout (a critical time), and again either before bed or in the middle of the night.