Branched Chain Amino Acids


Branched chain amino acids are a unique subset of essential amino acids. As a refresher, amino acids are the basic building blocks for proteins and are of incalculable importance in all physiologic processes. Amino acids are categorized as either essential or non-essential. When a specific amino acid is considered essential this simply means that the body cannot synthesis this type of amino acid and must obtain it from diet or supplementation.

The three BCAAs are leucine, isoleucine, and valine. BCAAs are versatile substances that can act as a fuel source for muscle during activity, can stimulate protein production, and can help prevent muscle breakdown.  Their branched side chain makes it easier for each amino acid to convert into energy during intense exercise. BCAAs make up 35 percent of all muscle tissue.

Potential Benefits of BCAAs in Musculoskeletal Health    


BCAAs may enhance muscle growth and strength 5,6,7

Muscle loss and weakness are frequent symptoms of chronic muscle and joint disease. Branch chained amino acids potentially stimulate the synthesis of new proteins. Research suggests branched chain amino acids initiate mRNA translation one of the key steps in protein synthesis. Leucine appears to be the most important branch chained amino acid to promote protein production.

Researchers from the University of Tokyo examined the effect of BCAA supplementation on strength performance. Study subjects consumed 6 grams of BCAAs prior to biweekly workouts. Compared to placebo, the  treatment group increased strength by 10%. (Ikeda et al. Effects and feasibility of exercise therapy combined with branched-chain amino acidsupplementation on muscle strengthening in frail and pre-frail elderly people requiringlong-term care: a crossover trial. Appl Physiol Nutr Metab. 2016 Apr;41(4):438-45. doi: 10.1139/apnm-2015-0436. Epub 2016 Jan 5.)



BCAAs may decrease muscle soreness, muscle break down, and fatigue 8,9,10,11

Research has demonstrated BCAAs reduce the blood concentrations of certain muscle proteins that are markers of muscle damage, like creatine kinase and lactic acid dehydrogenase. Moreover, BCAAs indirectly inhibit the production of the neurotransmitter serotonin. Serotonin is an important contributor to fatigue.

Australian researchers evaluated the effect of BCAA supplementation on muscle damage in the setting of endurance exercise. These results indicated that supplementary BCAA decreased blood concentrations of  intramuscular enzymes representative of muscle damage. This observation suggested that BCAA supplementation may reduce the muscle damage associated with endurance exercise.(Coombes et al. Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. J Sports Med Phys Fitness. 2000 Sep;40(3):240-6.)

BCAAs may promote sugar health 12,13

Diabetes has been associated with advanced joint and muscle deterioration. BCAAs facilitate blood sugar uptake by the liver and skeletal muscle. BCAAs also boost the storage of glucose (glycogenesis). Excess sugar floating around the blood stream is unhealthy since the sugar can cause harmful alteration to the structure and function of many different types of tissues, including joint and muscle tissue.

Korean Researchers investigated the effect of BCAA supplementation on glucose metabolism. Compared to placebo BSAA ingestion increased cellular uptake of glucose in the near term following exercise. (Dong-Hee Kim et al. Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances J Exerc Nutrition Biochem. 2013 Dec; 17(4): 169–180.)


BCAAs may enhance fat loss 14,15,16

Obseity is a major risk factor for chronic joint and muscle injury. Investigation implies BCAA supplementation enhances fatty acid oxidation. Fatty acid oxidation is the metabolic process in which the body preferentially uses fat for energy production, as opposed to using protein and/or sugar. Additional research findings also suggest BCAA consumption may reduce the risk of obesity.

French investigators examined the effect of branched chain amino supplementation combined with caloric restriction on elite wrestlers. Study subjects exhibited a 34% reduction in belly fat compared to baseline. (Mourier et al. Combined effects of caloric restriction and branched chain amino acid supplementation on body composition and exercise performance in elite wrestlers. Int J Sports Med. 1997 Jan;18(1):47-55.)

Are BCAAs beneficial for women as well?

BCAAs do not possess any gender-specific characteristics, meaning they can benefit men and women equally. However, pregnant and breastfeeding women are advised not to take BCAAs, and that’s simply because not enough research have been conducted to determine their safety on these populations.



Safety First

BCAAs are, for the most part, well tolerated. Most experts would agree that habitual supplementation maximizes their effectiveness. However, excess use can have potential bad side effects. Plus, BCAAs are not meant for people with certain conditions.

Common side effects from high doses of BCAA may include fatigue, nausea, loss of coordination, headaches, and greater insulin resistance.

As BCAAs are known to affect blood sugar levels, people undergoing surgery should avoid taking them for some time before and after surgery.

Prior to starting any supplementation discuss with a qualified medical professional familiar with your unique health history and needs.




  1. G. Wu, “Amino acids: metabolism, functions, and nutrition,” Amino Acids, vol. 37, no. 1, pp. 1–17, 2009.
  2. B. Skeie, V. Kvetan, K. M. Gil, M. M. Rothkopf, E. A. New- sholme, and J. Askanazi, “Branch-chain amino acids: their metabolism and clinical utility,” Critical Care Medicine, vol. 18, no. 5, pp. 549–571, 1990.
  3. Harper AE, Miller RH, Block KP. Branched-chain amino acid metabolism. Annu Rev Nutr. 1984;4:409–54.
  4. Rennie MJ. Influence of exercise on protein and amino acid metabolism. In: Rowell LB, Shepherd JT, editors. Handbook of physiology, section 12: exercise: regulation and integration of multiple systems. New York: Oxford University Press; 1996. p. 995–1035.
  5. Bolster DR, Jefferson LS, Kimball SR. Regulation of protein synthesis associated with skeletal muscle hypertrophy by insulin-, amino acid- and exercise- induced signalling. Proc Nutr Soc. 2004;63:351–6.
  6. Mordier S, Deval C, Bechet D, Tassa A, Ferrara M. Leucine limitation induces autophagy and activation of lysosome-dependent proteolysis in C2C12 myotubes through a mammalian target of rapamycin-independent signaling path- way. J Biol Chem. 2000;275:29900–6.
  7. Ikedat T et al. Effects and feasibility of exercise therapy combined with branched-chain amino acid supplementation on muscle strengthening in frail and pre-frail elderly people requiring long-term care: a crossover trial. Appl Physiol Nutr Metab. 2016 Apr;41(4):438-45. doi: 10.1139/apnm-2015-0436. Epub 2016 Jan 5.
  8. Sarah R. Jackman, Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans Front Physiol. 2017; 8: 390. Published online 2017 Jun 7. doi:  10.3389/fphys.2017.00390
  9. S. R. Kimball and L. S. Je erson, “Regulation of protein synthesis by branched-chain amino acids,” Current Opinion in Clinical Nutrition and Metabolic Care, vol. 4, no. 1, pp. 39–43, 2001. 

  10. Coombes JS, McNaughton LR. Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after pro- longed exercise. J Sports Med Phys Fitness. 2000;40:240–6.
  11.  Shimomura Y et al. Nutraceutical effects of branched-chain amino acids on skeletal muscle. J Nutr. 2006 Feb;136(2):529S-532S.
  12. Mordier S, Deval C, Bechet D, Tassa A, Ferrara M. Leucine limitation induces autophagy and activation of lysosome-dependent proteolysis in C2C12 myotubes through a mammalian target of rapamycin-independent signaling path- way. J Biol Chem. 2000;275:29900–6.
  13. Kim et al. Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances.  J Exerc Nutrition Biochem. 2013 Dec;17(4):169-80. doi: 10.5717/jenb.2013.17.4.169. Epub 2013 Nov 28.
  14. S. Nishitani, C. Ijichi, K. Takehana, S. Fujitani, and I. Sonaka, “Pharmacological activities of branched-chain amino acids: speci city of tissue and signal transduction,” Biochemical and Biophysical Research Communications, vol. 313, no. 2, pp. 387– 389, 2004.
  15.  S. Nishitani, T. Matsumura, S. Fujitani, I. Sonaka, Y. Miura, and K. Yagasaki, “Leucine promotes glucose uptake in skeletal muscles of rats,” Biochemical and Biophysical Research Commu- nications, vol. 299, no. 5, pp. 693–696, 2002. 

  16. Mourier A, Bigard AX, de Kerviler E, Roger B, Legrand H, Guezennec CY. Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers. Int J Sport Med. 1997;18:47–55.
  17. L. Q. Qin, P. Xun, D. Bujnowski et al., “Higher branched-chain amino acid intake is associated with a lower prevalence of being overweight or obese in middle-aged East Asian and Western adults,” Journal of Nutrition, vol. 141, no. 2, pp. 249–254, 2011.