Branched-chain Amino Acids
OTHER NAME(S): BCAA, BCAAs, branched-chain amino acids
Overview
Branched-chain amino acids (BCAAs) are a group of amino acids that includes leucine, isoleucine, and valine. BCAA supplements are sometimes used to build muscle, improve physical performance, or help with recovery after a concussion or brain injury. But their benefits for any use are not well defined. Although they appear to be well tolerated, there is not enough research to know what side effects they may cause. Before taking BCAA supplements, make sure to tell your health care provider about any health conditions you have or medicines you are taking.
Uses
What are branched-chain amino acids (BCAAs) used for?
Branched-chain amino acids (BCAAs) are used for various reasons, but their benefits are not well defined. Some common reasons that people use BCAAs include the following.
- To help with recovery from a concussion or traumatic brain injury (TBI)
- To help build muscle
- To improve physical performance
BCAA dietary supplements are available in various strengths and dosage forms. BCAAs are also added to many multi-ingredient products, including pre-workout supplements.
BCAAs may also be used for other conditions as determined by your health care provider.
Note: The FDA has not reviewed BCAAs for safety and effectiveness. Learn more about dietary supplements here.
How do BCAAs work (mechanism of action)?
Branched-chain amino acids (BCAAs) are amino acids with a specific type of chemical structure that includes a branched side chain. There are three BCAAs – leucine, isoleucine, and valine. Your body is not able to make these amino acids on its own, so you must get them from your diet. Many different foods contain BCAAs, including meats, fish, eggs, soy, nuts, beans, and dairy products.
Amino acids are the building blocks of protein, and your body uses BCAAs to make protein. BCAAs also seem to signal your body to make more protein overall. This effect is unique to BCAAs and does not seem to occur with other amino acids. As a result, some people take BCAA supplements to help build muscle and increase their energy levels during exercise. However, it is not clear if BCAA supplements can actually increase physical performance or muscle mass. If you are interested in building muscle, it may be more helpful to focus on getting enough protein in your diet every day. If you do not eat enough protein, your body will not be able to build more muscle.
Your body also uses BCAAs to make some important brain chemicals that send signals to your brain and nerves. There has been interest in using BCAAs to help people recover from a concussion or other brain injury. But research on this use is limited, and most studies gave BCAAs into a vein (IV). It is not clear if taking BCAA supplements by mouth can help with recovery any more than eating a healthy and well-rounded diet.
How should I store BCAAs?
You should store BCAAs according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.
Side Effects
What are the most common side effects of BCAAs?
BCAAs seem to be well tolerated. But there is not enough research to know what the common side effects may be. Tell your health care provider if you have any side effects that bother you.
There may be other side effects of BCAAs that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of BCAAs?
While less common, the most serious side effects of BCAAs are described below, along with what to do if they happen.
Severe Allergic Reactions. BCAAs may cause allergic reactions, which can be serious. Stop taking BCAAs and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Precautions
Who should not use BCAAs?
Allergies to Ingredients. People who are allergic to any of the following should not take BCAAs.
- Branched-chain amino acids (BCAAs)
- Isoleucine
- Leucine
- Valine
- Any of the ingredients in the specific product
Your pharmacist can tell you all of the ingredients in the specific BCAA products they stock.
What should I know about BCAAs before using them?
BCAAs are dietary supplements. They cannot be marketed to treat or cure a disease.
Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.
Keep BCAAs out of the reach of children.
If you are taking a BCAA powder, use an appropriate measuring device to measure the powder, such as the device included with the product. Read the label carefully and measure the amount stated on the label.
The FDA has not tested BCAA products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.
What should I tell my health care provider before using BCAAs?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if BCAAs are right for you.
In particular, make sure that you discuss any of the following.
Pregnancy. It is not known if or how BCAAs could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.
Breastfeeding. BCAAs are a normal part of breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Do BCAAs interact with foods or drinks?
There are no known interactions between BCAAs and foods or drinks.
It is unknown if drinking alcohol will affect BCAAs.
Do BCAAs interact with medicines (drug interactions)?
There are no known interactions between BCAAs and medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
The interactions between BCAAs and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with BCAAs is incomplete. Always check with your health care provider before taking BCAAs with any medicines.
Dosing
What should I do if I accidentally use too many BCAAs?
If you or someone else has used too many BCAAs, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
BCAAs are available in a wide range of forms and doses. Read the product label closely and speak to a health care provider about how to take BCAAs safely. Do not take double or extra doses, even if you miss a dose.
References
- EFSA Journal: “Scientific Opinion on the substantiation of health claims related to branched-chain amino acids (BCAA) and growth or maintenance of muscle mass (ID 442, 444, 445, 447, 448, 451, 1478), attenuation of the decline in muscle power following exercise at high altitude (ID 443), faster recovery from muscle fatigue after exercise (ID 447, 448, 684,1478), improvement of cognitive function after exercise (ID 446), reduction in perceived exertion during exercise (ID 450) and “healthy immune system” (ID 449) pursuant to Article 13(1) of Regulation (EC) No 1924/2006.”
- Frontiers in Nutrition: “Amino acid requirements of the infant: the amino acid composition of human breast milk.”
- Journal of the American Heart Association: “Circulating branched chain amino acids and cardiometabolic disease.”
- National Cancer Institute NCI Drug Dictionary: “Branched-chain amino acid supplement.”
- Nutrients: “Oral branched-chain amino acids supplementation in athletes: a systematic review.”
- National Library of Medicine: “Nutrition and Traumatic Brain Injury: Improving Acute and Subacute Health Outcomes in Military Personnel: Branched-Chain Amino Acids.”