Branched-chain amino acids are essential nutrients that help support muscle metabolism and are important for building muscle tissue protein. If you’re an athlete or bodybuilder, you may take oral supplements of branched-chain amino acids (BCAAs) to try to help with recovery from workouts and enhance athletic performance.

Studies suggest that BCAAs may prevent muscle breakdown during exercise. But they are not likely to help with athletic performance.

BCAAs may help:

• Bring on muscle growth
• Ease muscle soreness
• Feel less exercise fatigue
• Prevent muscle wasting
• Boost your appetite if you’re malnourished or have cancer
• Ease symptoms of tardive dyskinesia
• Ease symptoms of hepatic encephalopathy due to cirrhosis
• Protect people with cirrhosis from getting liver cancer
• Treat certain brain disorders
• Improve mental function in people with phenylketonuria

While it’s reported that BCAAs are helpful for diabetes or an inherited form of autism spectrum disorder, there isn’t enough evidence yet to support these uses.

Dosages of BCAAs vary, depending upon the reason for use. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it hard to establish a standard dose.