Branched-Chain Amino Acids

Medically Reviewed by Nayana Ambardekar, MD on November 18, 2022
2 min read

Branched-chain amino acids (BCAAs) are essential nutrients. They are proteins found in food. Your muscles "burn" these amino acids for energy.

The names of the specific amino acids that make up the branched-chain amino acids are leucine, isoleucine, and valine. The term branched-chain simply refers to their chemical structure.

BCAAs also may be taken in supplements. In some cases, health care providers may deliver BCAAs intravenously (by IV).

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.

You can get branched-chain amino acids from these foods:

  • Whey, milk, and soy proteins
  • Corn
  • Beef, chicken, fish, and eggs
  • Baked beans and lima beans
  • Chickpeas
  • Lentils
  • Whole wheat
  • Brown rice
  • Almonds, Brazil nuts, and cashews
  • Pumpkin seeds

Side effects.When taken up to 6 months, oral supplements of BCAAs have not often been linked with harmful side effects. However, side effects may include:

Risks.BCAAs may interfere with blood glucose levels during and after surgery. You may also be at increased risk if you have chronic alcoholism or branched-chain ketoaciduria.

Also, avoid using BCAAs if you are pregnant or breastfeeding.

Interactions.Talk with your doctor first if you are taking:

Tell your doctor about any supplements you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with medications or foods. They can let you know if the supplement might increase your risk.

The FDA does not regulate dietary supplements. However, it has approved an injectable branched-chain amino acid to counteract nitrogen loss.