You see a big dude walking around the gym with his gallon jug filled with a mysterious blue fluid. “Why’s he drinking windshield wiper fluid?”, you ask to yourself. No you silly goose, those are most likely BCAA’s.
For those of you that aren’t familiar, BCAA stands for Branched Chain Amino Acids. Amino acids are basically compounds that form chains (polypeptides) in order to create proteins in the body. As we all know, protein is essential for growth and repair.
There are essential and nonessential amino acids. Essential amino acids are those which the body can only obtain through diet and supplementation, whereas nonessential ones the body can make on its own. The branched chain amino acids fall into the category of essential amino acids. The branched chain amino acids are:
What’s so special about BCAA’s?
The most significant part of BCAA’s is the leucine component, which is the primary driver for the initiation of a process called protein synthesis. Protein synthesis is responsible for the growth of new cells, which is what we’re here for, right? This is why you see many BCAA supplements touting their ratios’ of BCAA’s that favor leucine in a 2:1:1 (leucine:isoleucine:valine) or even higher in favor of leucine. It’s not that the two other branched chain amino acids aren’t important, it’s just that they play much less of a role in muscle protein synthesis than leucine does.
Beware of Supplement Companies!
The sale of BCAA dietary supplements has skyrocketed over the past decade. This is because the companies that sell these supplements often tout them as being able to directly stimulate muscle protein synthesis, eliciting an anabolic response. It is also stated to improve recovery and reduce soreness, resulting in greater output. However, just realize this has become a multi-million dollar industry, and that you MUST be weary of what supplements you choose to purchase.
So What Does the Science Actually Tell Us?
The body is always in a constant state of turnover, which means that new protein is continuously being produced while older proteins are being destroyed (degraded). Nobody can be 100% anabolic at any point in time. Anabolic simply means that muscle protein synthesis exceeds the rate of muscle protein breakdown (catabolism).
However, supplementing with these is virtually useless at most, if not all, points in time. After consuming a meal with protein, your body will shift its turnover towards anabolism, given the meal contained all 9 essential amino acids, which for quick reference are:
Most people reading this consume adequate amounts of protein in a day (0.8g/kg of body weight minimum), so providing extra BCAA’s won’t really do much. Also, only providing 3 of the 9 amino acids doesn’t make much sense either. If only 3 of the essential amino acids are ingested, then the body must still find a way to get the other 6. If it’s not coming through the diet, guess where it’s coming from. That’s right, your own muscles (that catabolism we talked about earlier).
All essential amino acids (EAA’s) and nonessential amino acids are required for muscle protein synthesis (MPS). If not, than MPS will be severely limited. Therefore, it is theoretically impossible for BCAA supplementation in isolation to create an anabolic environment that favors muscle protein synthesis. 
Even Unconventional Methods Don’t Produce Significant Results
In one study by Louard et al. (oh yeah, side note, “et al.” is simply a Latin phrase meaning “and others” which indicates that other researchers were involved in the study, anyway…), BCAA’s were injected intravenously (into the vein) of 10 fasted (aka post-absorptive in the scientific literature), definitely not the way most people would prefer to take their BCAA’s!
Surprisingly, the infusion of BCAA’s DECREASED protein synthesis to a statistically significant degree. However, protein breakdown was decreased as well. Since the balance between protein synthesis and breakdown remained negative, the state of catabolism persisted and no anabolic environment was produced . If a 100% rate of bio-availability doesn’t work through injection, than oral administration (all BCAA supplements) will definitely not produce significant results.
However, Not to Worry!
EAA’s are released into what’s called the free intracellular pool. These are the amino acids that are available to be broken down in order for the body to obtain the EAA’s it needs. However, ~70% of EAA’s are reabsorbed back into muscle protein . The rate at which EAA’s can be reincorporated back into protein synthesis (thus saving it from breakdown) is very limited and is very difficult to change. Therefore, any supplemental intervention is moot.
A dietary BCAA supplement by itself CANNOT increase protein synthesis; it’s physiologically impossible. The presence of the other EAA’s will slow down any possible acceleration of protein synthesis due to their varying absorption rates.
The only scenarios in which I see BCAA supplementation to be appropriate is during times of illness when solid foods and viscous protein drinks aren’t possible to consume. Also, those who are suffering from muscle-wasting diseases, such as cancer, MAY benefit from this. However, this is only speculation, as there is a scarcity of data on these specific conditions in relation to BCAA supplementation.
So please, spend your money wisely. You work hard for it. Don’t fill these dishonest companies’ pockets that tout you’ll experience “extreme gainz” from this. Buy something that works. Whey protein, creatine, FOOD! But please, I beg of you, not BCAA’s.
- 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
- Louard, R. J., Barrett, E. J., & Gelfand, R. A. (1990). Effect of Infused Branched-Chain Amino Acids on Muscle and Whole-Body Amino Acid Metabolism in Man. Clinical Science,79(5), 457-466. doi:10.1042/cs0790457