Branched-Chained Amino Acids (BCAA)

Supplementing with BCAA has become very popular because it is considered an essential supplement by many natural lifters.  However, do you know what their function is?  Are they a bodybuilding necessity or a waste of money?  To answer these questions, in this article we will take a deep dive into what makes up the BCAA and what their effects are in relation to bodybuilding.


Fig 1. BCAAs

Table of Contents

What are the BCAAs?

Branched-chain amino acids (BCAA) are essential nutrients that the body obtains from proteins.  The most common sources are meat, dairy products, and legumes.  Usually, the BCAA will include leucine, isoleucine, and valine.  They are given the name “branched-chain” because of the chemical structure of the amino acids.


Leucine is considered by many to be the “main” amino acid of the three BCAA’s, since it is the most effective one in muscle building.  In fact, leucine is stronger than the other two BCAA’s, so 5 grams (g) of leucine will be more effective than 5g of a mixed BCAA powder or a cap.  Furthermore, studies on leucine supplementation have shown it to be effective at promoting muscle gains, especially among people with a lower protein intake and the elderly.


Isoleucine is the intermediate BCAA in terms of potency - it is weaker than leucine, but yet stronger than valine.  In multiple studies it has shown the ability to increase glucose uptake and the usage of glucose during exercise.  Due to this effect, isoleucine is important as part of a preworkout drink or meal, and even more so if you are not on a low carbohydrate diet.


Valine is the weakest of the three BCAA’s.  When used as a standalone there is no benefit that could not be replicated by leucine or isoleucine.  Interestingly, valine seems to be more similar to leucine than isoleucine, but it shares similar insulin resistance with isoleucine.

Benefits of BCAA Supplementation

BCAA are considered the “building blocks” of the body as they make up to 35% of your muscle mass.  They build cells, repair tissue, form antibodies, build RNA and DNA, and carry oxygen throughout the body.  Remember, during weight training the body naturally becomes highly catabolic, so when glycogen stores are depleted the body will soon turn to muscle for energy.  However, BCAA supplementation basically tells the body to continue forward with protein synthesis when the body naturally wants to stop it, helping avoid these catabolic processes.  For best effects of the BCAA, a good dose would be 4-8g before training, and another 4-8g immediately post workout.

Is BCAA Supplementation Overrated?

There are two main arguments against using BCAA as a supplement.  The first argument claims that studies showing the benefits of BCAA were done on subjects who weren’t getting enough protein in their diet.  While the second one says that you can simply get your BCAA from food, since studies show no evidence that supplementing with BCAA is more effective for the purpose of muscle building than food, or whey protein.


BCAA can be a very effective supplement if training in a fasted state or you are lacking enough protein in your diet.  Overall, if you are on the fence about adding them to your regimen, give them a try for yourself.  They are relatively cheap, and come in powders of all flavors, as well as capsules.  Unfortunately, supplement companies often add sugars, fillers, and even caffeine to BCAA.  Therefore, you should make sure to read the ingredient profile before purchasing a particular product, so you always know what you are putting in your body.


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