theguerillachemist

This recently published study is a meta analysis of all the literature(studies) about BCAA supplementation and protein synthesis. This paper uses not only oral supplementation, but intravenous supplementation of BCAA and the conclusion the researchers made will upset a lot of supplement companies: BCAA supps do not increase protein synthesis. The authors go on to say that EAA are required to significantly increase the rate of muscle protein synthesis, and must be present either from food or muscle breakdown. As EAA cannot be synthesized by your body, they must be consumed through diet and may be the rate limiting step for increasing MPS. This is why it is always recommended that your protein source be a complete protein including all EAA, should be consumed every 3 hours in order to keep MPS elevated. While Leucine can activate mTOR, one pathway for increasing MPS, EAA must be present in order to actually increase production of new muscle. It was noted that taking leucine alone may decrease plasma concentrations of valine and isoleucine. This may be why long term studies of leucine supplementation has failed to show positive results. Also, all BCAA and some EAA use the same active transporters to get into cells, which means that they all compete to bind to these transporters. I have been preaching for years that EAA are vital to muscle growth and not just BCAA. Bottom line: Eat whole food protein sources or include EAA with your BCAA in order to maximize MPS