BCAA supplements don’t contain all nine of the essential amino acids, while whey protein does, and as a result, your muscle response won’t be as high as it could be.
In the study, 10 young men with experience lifting completed two separate workouts, each containing both the leg press and leg extension. Immediately after one session, they drank a branched-chain amino acid (BCAA) beverage with 2.6 grams (g) leucine, 1.4 g isoleucine, and 1.6 g valine. After the other session, they drank a placebo beverage that contained no branch-chain amino acids.
When the guys drank their BCAA drink, it stimulated a 22 percent greater muscle-protein synthesis response—the rebuilding of muscle tissue to repair micro-tears caused by training—than when they drank their placebo beverage.
Sounds great, right? But the magnitude of that response was about 50 percent less than which was previously reported after a 20-gram dose of whey protein—which contains a similar amount of BCAAs—following resistance training.
That’s because BCAA supplements don’t contain all nine of the essential amino acids, while whey protein does. As a result, your muscle response won’t be as high as it could be.
“A sufficient amount of the full complement of amino acids is necessary for maximum muscle building, following exercise,” study author Kevin D. Tipton, Ph.D., said in a statement. “Athletes interested in enhancing muscle growth with training should not rely on these BCAA supplements alone.”
In fact, it’s unlikely that you even need BCAAs if you’re already taking in enough protein, as we reported. If you eat two to three grams of leucine—likely the muscle-building powerhouse—from food sources at least three times a day, you should be good to go, nutritionist Chris Mohr, Ph.D., R.D., writes. For instance, 3 ounces of grilled chicken breast contains 2.1 g of leucine, while 4 ounces of 1% cottage cheese contains 1.4 ounces of leucine.