BCAA Supplementation

Does BCAA Supplementation Improve Running Performance?


For those unfamiliar, BCAA is a type of dietary supplement marketed toward athletes as performance-enhancing. The letters stand for Branched Chain Amino Acids. Have you already included a BCAA supplement in your running regime? Are you looking to learn more about how useful or effective they really are? This article will be a good source of answers to your questions.

Are you a long-distance runner? Has a fellow athlete or health professional advised you to ingest BCAAs for ergogenic (i.e. performance-enhancing) purposes?  In any case, here you are: probably wondering just how useful this supplement really is. To satiate your curiosity, we’ve gone ahead and summarized and simplified the latest findings from scientific literature.

What are BCAAs?

BCAAs, or Branched Chain Amino Acids, are comprised of three essential amino acids, known as “branched chain” (with a molecular structure taking the form of a chain): leucine, isoleucine, and valine.

They are essential because our body is not able to generate them on its own, which means we must consume them via food (meat, fish, dairy products, split peas, pistachios, etc.)

BCAAs can also be consumed via dietary supplement, which is a popular choice for runners.

BCAA production

BCAA supplements used to be derived from human hair via hydrolysis, as well as from pig hair and good feathers, then separated via centrifuge and filtered. The issue with this process is that it can result in a high concentration of heavy metals. In the past few years, BCAAs have been obtained via a bacterial fermentation process (Corynebacterium glutamicum and Escherichia coli) of glucose derived from plants (vegan BCAAs). The downside to this extraction technique is that it is often more expensive.

Commercially available BCAA products

Sold in powder or capsule form, the ratio of the different amino acids can vary from product to product:

  • 2:1:1 corresponds to 2 grams of leucine for every 1 gram of isoleucine and 1 gram of valine. This is the most common ratio on the market, and the closest to the ratio that naturally occurs in the muscle. For this reason, it is the generally preferred model for BCAA supplements.
  • 4:1:1 (4 leucine, 1 isoleucine, 1 valine), with an even higher presence of leucine, is considered to have greater anabolic power (muscle synthesis). For this reason, it is the preferred ratio for bodybuilders. However, too much leucine in proportion to the other two branched chain amino acids may have a catabolic effect (destruction of muscle cells).
  • 8:1:1 with an even higher proportion of leucine
  • 10:1:3, and so on…

Other molecules can be added to the BCAA recipe, including L-Glutamine, Vitamin B6, Vitamin C, magnesium, Rhodiola, etc.

Why take a BCAA supplement?

Brands that sell BCAA supplements advocate their use for several reasons:

  • Aid in muscle gain and muscle repair following physical exertion
  • Help fight against the loss of muscle mass during training
  • Optimize athletic performance by reducing the muscles’ oxygen requirements
  • Support weight loss (by limiting the loss of muscle mass) during a low-calorie diet

BCAAs and improved fitness levels

Numerous studies have shed light on the effects of BCAA supplements on athletes. The general results indicate that BCAAs:

  • Reduce muscle loss during exercise [1], minimizing pain and maximizing recovery [2,3]
  • Allow for greater isometric muscular contraction power (gains) compared with no BCAA supplement [4]
  • Decrease loss of cognitive ability during endurance feats [5]

Experts’ opinion on BCAA supplementation

Despite these findings, the data collected has been criticized due to the small sample size of subjects present in each of these studies. Moreover, other teams have failed to show in their own studies that BCAA supplementation has any significant impact on athletic ability [6,7,8].

Consuming BCAA supplements does not have dangerous health consequences as long as the quantity ingested does not exceed the needs of the body. The average recommended dosage is 5g per day. Like any other amino acid or protein-based supplement, an overdose can result in side effects of nausea, diarrhea, gastrointestinal disorders, fatigue, impaired motor skills, and kidney failure.


[1] MacLean, D. A., Graham, T. E., & Saltin, B. (1994). Branched-chain amino acids augment ammonia metabolism while attenuating protein breakdown during exercise. American Journal of Physiology-Endocrinology And Metabolism, 267(6), E1010-E1022.

[2] Coombes, J. S., & McNaughton, L. S. (2000). Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. Journal of sports medicine and physical fitness, 40(3), 240.

[3] Nosaka, K., Sacco, P., & Mawatari, K. (2006). Effects of amino acid supplementation on muscle soreness and damage. International journal of sport nutrition and exercise metabolism, 16(6), 620-635.

[4] Shimomura, Y., Murakami, T., Nakai, N., Nagasaki, M., & Harris, R. A. (2004). Exercise promotes BCAA catabolism: effects of BCAA supplementation on skeletal muscle during exercise. The Journal of nutrition, 134(6), 1583S-1587S.15

[5] Hassmén, P., Blomstrand, E., Ekblom, B., & Newsholme, E. A. (1994). Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance. Nutrition (Burbank, Los Angeles County, Calif.), 10(5), 405-410.

[6] Davis, J. M., Alderson, N. L., & Welsh, R. S. (2000). Serotonin and central nervous system fatigue: nutritional considerations. The American journal of clinical nutrition, 72(2), 573S-578S.

[7] Hargreaves, M., & Snow, R. (2001). Amino acids and endurance exercise. International Journal of Sport Nutrition and Exercise Metabolism, 11(1), 133-145.

[8] Watson, P., Shirreffs, S. M., & Maughan, R. J. (2004). The effect of acute branched-chain amino acid supplementation on prolonged exercise capacity in a warm environment. European journal of applied physiology, 93(3), 306-314.

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