Do BCAAs Actually Build Muscle? Not As Much As You Think

This supplement might be selling your muscles short

Christa Sgobba |

Your post-workout recovery drink might be selling your muscles short: Taking branched-chain amino acids by themselves likely isn’t enough to maximally stimulate your muscle-building response, new research out of University of Stirling in the UK suggests.

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.

Related: How Much Protein Can Your Muscles Absorb In One Sitting?

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.

Related: 3 Muscle-Building Snacks You Can Make With Protein Powder

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 Dr. Kevin D. Tipton, said in a statement. “Athletes interested in enhancing muscle growth with training should not rely on these BCAA supplements alone.”

Related: 3 Supplements That You Really Need In Your Diet, And 3 That Are Just Wasting Your Money

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 Dr. Chris Mohr, writes. For instance, 85 grams of grilled chicken breast contains 2.1 g of leucine, while around 110 grams of 1% cottage cheese contains around 40 grams of leucine.

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