Branched chain amino acids (BCAAs) have become one of the most popular supplements in the fitness industry. Both as a standalone product and ingredient in protein supplements, pre-workouts, and recovery drinks, BCAAs are everywhere. At approximately $18 per pound, its high price SHOULD deliver great results, right?

What are BCAAs?

There are 20 amino acids that make up muscle protein (or muscle tissue). Of those, nine are essential (the body cannot make them, we need to get them from our diet) and 11 are non-essential (the body can make them). Out of the nine essential amino acids, three are known as branched chain amino acids: leucine, isoleucine, and valine. These three amino acids are thought to have a special role in increasing performance1.

How do BCAAs work and what are some potential benefits BCAAs provide?

The body digests protein in a somewhat lengthy process. First, hydrochloric acid breaks large protein molecules into smaller ones. Next, the pancreas secretes an enzyme known as protease that breaks large amino acid chains into free amino acids2.

Most amino acids are broken down in the liver before they are transported to other tissues such as skeletal muscle. The exception to this is BCAAs. Free BCAAs are transported directly to the bloodstream. They get delivered to skeletal muscle much faster than other amino acids2.

Potential Benefits from BCAAs

While in skeletal muscle, BCAAs have a few important roles. Muscle tissue contains 60% of the specific enzymes required to utilize BCAAs as energy. This makes BCAAs an important and quick source of energy for muscles during exercise. Depending on the type of exercise, BCAAs account for up to 20% (some believe even more) of energy needs2.

Leucine, one of the BCAAs, is thought to be especially important. The body’s need for leucine is 25 times greater than the amount of leucine that’s readily available. When the amount of available leucine is insufficient, the body breaks down muscle tissue to provide the rest. Providing leucine before or during a workout can alleviate the shortage and prevent unnecessary muscle breakdown.  Some amino acids also trigger the muscle to increase protein synthesis; leucine is one of them2.

BCAAs can also prevent fatigue. As the duration of exercise increases, cellular energy decreases with the loss of glucose and glycogen. ATP (the muscle’s energy currency) levels can be maintained through the breakdown of BCAAs2.

BCAAs may also increase fat loss. Some studies have shown leucine acts on fat cells to release fat for use as energy. Finally, leucine may prevent muscle degradation during weight loss and calorie restriction2.

The Bottom Line

BCAAs have been credited with reducing muscle soreness, preventing fatigue, increasing strength, decreasing muscle breakdown during cardiovascular activity and calorie deficits, and improving recovery. In this series, we’ll  see whether the research supports theses claims or not.

  • BCAAs and Strength Training
  • BCAAs and Aerobic Exercise – coming soon
  • BCAAs and Protein Synthesis – coming soon
  • BCAAs and Body Composition – coming soon
  • BCAAs and Recovery – coming soon
  • BCAAs and Dieting – coming soon


  1. Wolfe, R. R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: Myth or reality? Journal of the International Society of Sports Nutrition,14(1). doi:10.1186/s12970-017-0184-9
  2. Sowers, S. (2009). A Primer On Branched Chain Amino Acids. Retrieved from https://www.huhs.edu/literature/BCAA.pdf
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