Branched-chain amino acids (BCAAs) are three of the nine essential amino acids needed for survival. They include leucine, isoleucine, and valine.
Since your body does not produce BCAAs, you must get them through foods or supplements. Most people consume enough BCAAs if they eat a balanced diet. Amino Acid Powder
Claims that BCAAs can improve muscle mass and exercise performance have made them popular among athletes and those seeking ways to enhance fitness. While BCAA supplements are safe for most people, they should be taken cautiously.
This article explains how BCAAs affect your body, how to increase them, and how they can help. It also includes side effects, warnings, and pros and cons of adding to normal BCAA levels.
Amino acids are the "building blocks" of proteins, which are necessary for the growth of healthy muscles, skin, hair, blood, bones, and more. Amino acids also impact metabolism.
Branched-chain amino acids are so named because of their chemical structure. Unlike other amino acids, which are broken down in your liver, BCCAs are broken down in muscle tissue.
BCAAs stimulate protein synthesis, and as a result, stimulate an anabolic response (the process by which your muscles repair and grow in response to the stress of exercise).
Branched-chain amino acids also convert to glucose during exercise more easily than other types of amino acids. Your body uses glucose for energy.
These responses may help improve exercise performance, build muscle mass, and improve exercise recovery.
Essential amino acids include the nine amino acids that your body is unable to produce but you need for normal function. You must get them from foods or supplements.
Essential amino acids include histidine, lysine, methionine, phenylalanine, threonine, tryptophan, and the three BCAAs—isoleucine, leucine, and valine.
Nonessential amino acids are the 11 amino acids that your body can produce even if you don't consume them. These amino acids are not required by your body for proper function, but they do contribute to your overall health.
Nonessential amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.
You can increase BCAA intake by consuming a protein-rich diet. BCAA foods include the following:
BCAA powder and oral supplements are available as over-the-counter products. Formulations vary by manufacturer and specific product. A typical formulation is leucine, isoleucine, and valine in a 2-to-1-to-1 ratio. There is no set value for the intake of BCAAs.
BCAA supplements are usually consumed by athletes and others who participate in regular, moderate physical activities at various practice levels. They are typically safe for most healthy individuals to take daily. For optimal benefits, taking BCAAs before or after your workout is advised.
Six benefits of BCAAs are:
Research indicates that BCAAs can reduce delayed onset muscle soreness (DOMS), the muscle soreness that occurs between 12 and 24 hours after exercise. Supplementing with BCAAs before exercise may reduce postexercise muscle soreness and accelerate recovery time.
In a systematic review, researchers reported that muscle damage was limited with daily BCAA supplementation of greater than 200 milligrams per kilogram of body weight (mg/kg) for longer than 10 days and starting at least seven days before performing the damaging exercise.
Researchers reported evidence that BCAAs stimulated 22% greater muscle protein synthesis (the process involved in making muscle) than placebo (an ineffective substance given to people in a control group) when used after resistance exercise. The findings were based on the results of participants who consumed a drink of BCAAs after their resistance workouts.
Taking BCAA supplements may improve exercise endurance and reduce exercise fatigue.
In one study, participants who took BCAA supplements before exercise had lower serotonin blood levels than those who took a placebo. Serotonin contributes to central fatigue. Central fatigue is the mental fatigue that occurs during extended aerobic workouts. Those who took BCAAs also had improved energy metabolism.
BCAAs may help people maintain muscle mass, which can become depleted as body protein is lost in certain illnesses like cancer. Research indicates that a high-protein diet that includes additional BCAAs, especially leucine, can help maintain muscle mass in these conditions.
Countering the Effects of Advanced Liver Cirrhosis
BCAA supplements have value as a nutritional intervention for preventing complications in liver disease. They have been shown to improve quality of life and prognosis in people with liver cirrhosis , an advanced stage of liver disease.
Separate studies have also shown that BCAA supplementation can improve signs and symptoms of hepatic encephalopathy (the loss of brain function that occurs with advanced liver disease), weakness and fatigue, and sleep disturbances.
Research suggests that BCAAs may have multiple roles in insulin resistance (the inability of cells to take up blood sugar) by regulating blood sugar levels and encouraging cells to accept more sugar from your blood.
Many people consume high amounts of amino acids as dietary supplements without side effects. However, side effects of consuming too much BCAA can vary based on your age, health conditions, diet, and medications.
While there are inconsistencies regarding the presence of side effects from too much BCAA, the most common reactions include the following:
These effects seem temporary when they occur and are often limited to the early administration period.
Other possible side effects of BCAA supplementation may include the following:
Due to a lack of research, little is known about the potential adverse effects and interaction of BCAAs with other chemicals. If you have a chronic condition and/or take daily medication, check with your healthcare provider before taking BCAA supplements.
There are no known interactions between BCAAs and other supplements, foods, or compounds. No studies have found definitive interactions between BCAAs and specific medications, though that is not to infer that those interactions do not exist.
Research is inadequate regarding the safety of using BCAA and other amino acid supplements for the following groups:
People with maple syrup urine disease (MSUD), a rare congenital disorder, should not take BCAAs. This disease interferes with the proper breakdown of BCAAs. Consuming too many BCAAs could lead to an accumulation of toxic BCAA products linked to nerve and brain symptoms.
While more research is needed, people who have amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) or a high risk of the disease should avoid BCAAs. Higher levels of BCAAs have been observed in people with ALS, though a pooled analysis of five cohort studies did not find any link between BCAAs and ALS risk.
In one study, supplementation of 60 grams (g) of BCAA altered the blood levels of tryptophan, phenylalanine, and tyrosine, which could cause depression in susceptible people. People with a history of depression should consult their healthcare provider before using BCAA supplements.
Whether BCAA supplements are right for you depends on your goals and overall condition. Your healthcare provider can help you decide whether you can benefit from BCAA supplements.
Consider the following pros and cons of adding BCAA supplements to your routine.
Pros of taking BCAA supplements:
Cons of taking BCAA supplements:
BCAAs include leucine, isoleucine, and valine. While your body needs these three amino acids for normal function, it cannot produce them. You have to consume them through food or supplements.
Some research suggests that BCAAs may promote muscle growth, prevent muscle loss, and decrease muscle soreness after working out. There is also evidence that they can improve the signs and symptoms of people with advanced liver disease.
While high levels of BCAAs are safe for most people, they may increase your risk of having certain health problems. Consult your healthcare provider before adding BCAA supplements to your diet.
Holeček M. Branched-chain amino acids in health and disease: metabolism, alterations in blood plasma, and as supplements. Nutr Metab (Lond). 2018;15:33. doi:10.1186/s12986-018-0271-1
Nie C, He T, Zhang W, Zhang G, Ma X. Branched chain amino acids: beyond nutrition metabolism. Int J Mol Sci. 2018;19(4):954. doi:10.3390/ijms19040954
American Dairy Association. Branched chain amino acids (BCAAs) and sports performance.
University of Rochester Medical Center. Leucine.
Harvard Health Publishing Harvard Medical School. High-protein foods: the best protein sources to include in a healthy diet.
Fouré A, Bendahan D. Is branched-chain amino acids supplementation an efficient nutritional strategy to alleviate skeletal muscle damage? A systematic review. Nutrients. 2017;9(10):1047. doi:10.3390/nu9101047
Martinho DV, Nobari H, Faria A, Field A, Duarte D, Sarmento H. Oral branched-chain amino acids supplementation in athletes: a systematic review. Nutrients. 2022;14(19):4002. doi:10.3390/nu14194002
Jackman SR, Witard OC, Philp A, Wallis GA, Baar K, Tipton KD. Branched-chain amino acid ingestion stimulates muscle myofibrillar protein synthesis following resistance exercise in humans. Front Physiol. 2017;8:390. doi:10.3389/fphys.2017.00390
Kim DH, Kim SH, Jeong WS, Lee HY. Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances. J Exerc Nutrition Biochem. 2013;17(4):169-180. doi:10.5717/jenb.2013.17.4.169
Jonker R, Engelen MPKJ, Deutz NEP. Role of specific dietary amino acids in clinical conditions. Br J Nutr. 2012;108(0 2):S139-S148. doi:10.1017/S0007114512002358
Bischoff S, Bernai W, Dasarathy S, et.al. ESPEN practical guideline: clinical nutrition in liver disease. Clinical Nutrition. 2020;39(12):P3533-3562. doi:10.1016/j.clnu.2020.09.001
Tajiri K, Shimizu Y. Branched-chain amino acids in liver diseases. Transl Gastroenterol Hepatol. 2018;3:47. doi:10.21037/tgh.2018.07.06
Shou J, Chen PJ, and Xiao WH. The effects of BCAAs on insulin resistance in athletes. J Nutr Sci Vitaminol, 2019;65;353-389.
Cogo E, Elsayed M, Liang V, et al. Are supplemental branched-chain amino acids beneficial during the oncological peri-operative period: a systematic review and meta-analysis. Integr Cancer Ther. 2021;20:1534735421997551. doi:10.1177/1534735421997551
Ullrich SS, Fitzgerald PC, Schober G, et al. Intragastric administration of leucine or isoleucine lowers the blood glucose response to a mixed-nutrient drink by different mechanisms in healthy, lean volunteers. Am J Clin Nutr. 2016;104(5):1274-1284. doi:10.3945/ajcn.116.140640
Ananieva EA, Wilkinson AC. Branched-chain amino acid metabolism in cancer. Curr Opin Clin Nutr Metab Care. 2018;21(1):64-70. doi:10.1097/MCO.0000000000000430
University of Wisconsin-Madison School of Medicine and Public Health. Study: diet limiting specific amino acids may be key to weight loss.
Zhang F, Zhao S, Yan W, et al. Branched chain amino acids cause liver injury in obese/diabetic mice by promoting adipocyte lipolysis and inhibiting hepatic autophagy. EBioMedicine. 2016;13:157-167. doi:10.1016/j.ebiom.2016.10.013
Kaiser Permanente. Branched-chain amino acids.
Holeček M. Side effects of amino acid supplements. Physiol Res. 2022;71(1):29-45. doi:10.33549/physiolres.934790
Holeček M. Branched-chain amino acids in health and disease: metabolism, alterations in blood plasma, and as supplements. Nutr Metab (Lond). 2018;15:33. doi:10.1186/s12986-018-0271-1
Blackburn PR, Gass JM, Vairo FP e, et al. Maple syrup urine disease: mechanisms and management. Appl Clin Genet. 2017;10:57-66. doi:10.2147/TACG.S125962
Bjornevik K, O’Reilly ÉJ, Berry JD, et al. Prediagnostic plasma branched-chain amino acids and the risk of amyotrophic lateral sclerosis. Neurology. 2019;92(18):e2081-e2088. doi:10.1212/WNL.0000000000006669
International Sports Sciences Association (ISSA). Do BCCAs break a fast? And, does it matter?
By Anna Giorgi Anna Zernone Giorgi is a writer who specializes in health and lifestyle topics. Her experience includes over 25 years of writing on health and wellness-related subjects for consumers and medical professionals, in addition to holding positions in healthcare communications.
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