BCAA’s

TheMagicOneMikeD wrote: »

No one is claiming it will make you hulk up overnight, but I see source after source after source saying that supplementing with Leucine does lead to increased hypertrophy for a short period after taking it.

I may be mistaken but I don't recall seeing anywhere that it only works if there is a protein deficiency.

So, I guess I already have my answer but no one here believes there is any point in supplementing with BCAA's, specifically 3g + of leucine if you're weight training?

And if you see no upside in it do you see any downside, except for spending a few dollars on it? Like any adverse health effects?

...An extensive search of the literature has revealed no studies in human subjects in which the response of muscle protein synthesis to orally-ingested BCAAs alone was quantified, and only two studies in which the effect of intravenously infused BCAAs alone was assessed. Both of these intravenous infusion studies found that BCAAs decreased muscle protein synthesis as well as protein breakdown, meaning a decrease in muscle protein turnover. The catabolic state in which the rate of muscle protein breakdown exceeded the rate of muscle protein synthesis persisted during BCAA infusion. We conclude that the claim that consumption of dietary BCAAs stimulates muscle protein synthesis or produces an anabolic response in human subjects is unwarranted...


...Thus, it might be expected that leucine alone would be more effective than the combination of all of the BCAAs. However, there are two significant limitations of a dietary supplement of leucine alone. First, the same issues that limit the extent of stimulation of muscle protein synthesis by BCAAs alone regarding the availability of the other EAAs necessary for the production of intact muscle protein also limit the response to leucine alone. Second, elevation of the plasma concentration of leucine activates the metabolic pathway that oxidizes all of the BCAAs. As a result, ingestion of leucine alone results in a decrease in the plasma concentrations of both valine and isoleucine. The availability of valine and isoleucine may therefore become rate limiting for muscle protein synthesis when leucine alone is consumed. This may be why long-term outcome studies with dietary leucine supplementation have failed to yield positive results... [25].

...In summary, overall, based on the available evidence, the best nutritional recommendation to optimize adaptations to training, including muscle hypertrophy and enhanced oxidative metabolism, would still be to eat sufficient high-quality protein (that naturally includes BCAA, of course) in the context of meals. At present, we do not believe there is sufficient evidence to recommend BCAA supplements for enhancing muscle anabolism or alleviating muscle damage or, for that matter, for any other reason.