In recent years, branched-chain amino acid supplements have come back into vogue in the bodybuilding and fitness community, and with good reason. There’s more research that supports the use of BCAAs than most other supplements on the market.
While BCAA supplementation may be useful for gaining mass, I believe BCAAs are especially helpful for maintaining muscle mass while on a calorie-deficit diet. They’re particularly useful for bodybuilding competitors who take their physiques to the lean extreme.
Although dieting down makes you look awesome onstage, on the beach, and to your friends of the opposite sex, it can also take a chunk out of your muscle mass.