Branched Chain Amino Acids, BCAA: What's The Story?

Every bodybuilder/strength athlete has been told that during reduced calorie periods such as the precontest phase, they should take Branched Chain Amino Acids (BCAA) multiple times a day to sustain muscle growth and prevent catabolism of muscle. The three BCAA—L-Leucine, L-Valine, and L-Isoleucine—have been heavily researched as a preventative, even therapeutic, measure to combat muscle-wasting diseases. 

We all know that amino acids are the “building blocks of protein“ and protein is essential for building muscle, but why are these three amino acids so special? Unlike the other 17 standard amino acids, BCAA aren’t metabolized by your liver. These instead pass through the liver into systemic circulation. 60% of the BCAA are then metabolized by skeletal muscle into branched chain keto acids. These are incorporated into protein or used directly as energy by the skeletal muscle and organs like the heart, brain, liver and kidneys. 

BCAA also play an important role in protein turnover, or increased protein synthesis and decreased protein degradation. Their role as the muscles’ energy source is one way, and they are also key synthesizers of two other amino acids, L-Glutamine and L-Alanine. 

L-Glutamine is well known as protein synthesizer, cellular energy source and for improving nitrogen balance so anabolic processes will occur. For anybody trying to build muscle, this is a necessity.

L-Alanine is a major precursor for gluconeogenesis in the liver. Gluconeogenesis gives working muscle extra glucose to utilize. 

So BCAA are important physiologically, but how do they apply to exercise? 

Studies show exercise increases skeletal muscle metabolism of BCAA by ten times the amount of normal resting values (1). This depletes BCAA, as well as Glutamine and Alanine, levels. You need to have a readily available source of these during—and especially after—your workout to facilitate muscle recovery. In one study, a BCAA solution improved the recovery of muscle force of an isolated rat diaphragm by 20-30%, when compared to standard amino acid solutions (1). For bodybuilders and athletes, this is huge. Drinking BCAA during a workout is encouraged because skeletal muscle can instantly use them for energy.

So if you haven’t been using BCAA, start! I guarantee you will notice a difference in endurance and your end-of-workout strength. 

From experience, I’ll say that the addition of BCAA will absolutely improve your muscle gains if you do it correctly. For my most recent contest prep, I was doing a modified keto diet for the last eight weeks and doing cardio three times a day because I was behind schedule with my fat loss. My calorie intake was very low and my calorie expenditure was extremely high. I reached the point where I barely had energy for anything—let alone working out. I began mega-dosing BCAA at 10g per dose. Doses were taken at pre-morning cardio, post-morning cardio, pre-workout, post-workout, and before bed. At three days out, I weighed 223 and was sub 3% body fat. This means I had lost about five pounds of body fat, yet had only lost one pound of bodyweight. There is always a fluctuation in bodyweight with water levels, however I am positive that I added muscle due to the way my physique looked.

So here is what I recommend:

  • Offseason: take 5g of BCAA per dose
  • Precontest: 10g BCAA per dose, multiple times daily: 1) upon waking, 2) pre-workout, 3) post-workout, and 4) before bed. Enjoy the results!

1)  Branched Chain Amino Acids.  Platell, Kong, McCauley, Hall.  Journal of Gastroenterology and Hepatology.  Volume 15. Issue 7.  Pages 695-812.  July 2000.