BCAAs: a muscle building jackpot or just a fitness fad? BCAAs were once a niche market that only the most results-savvy fitness enthusiasts and athletes dove into, but has not exploded to become one of the most commonly used nutritional supplements out there. Whether you’re looking for muscle growth, fat loss, or better performance, BCAAs seem to play a role in some capacity. So naturally, like a good protein powder or a pre-workout, BCAAs have made it as a staple in any athlete or bodybuilder’s diet. Simply put, they’ve earned their rite of passage in the sports nutrition world.
But when it comes to why people choose to use BCAAs–because they’re certainly not “essential” –there’s one specific area where BCAAs excel and other supplements may fall short. Whether you’re smack in the middle of a cutting phase, favour fasted training over fed, or following a ketogenic diet to fine-tune your performance, BCAAs may just be your gold for maintaining muscle mass.
We’re diving into details on one of the most widely consumed fitness supplements out there and whether they’re worth adding to your stack. You’re asking yourself, are BCAAs a muscle building jackpot or just a fitness fad? Let’s find out!
What Are BCAAs?
The branched chain amino acids, which you probably know as the BCAAs, are a group of three essential amino acids—leucine, isoleucine, and valine—that have been isolated from their 6 sibling amino acids due to their role in muscle growth. While there are 20 amino acids in total, only nine of those are essential, meaning they must be obtained through diet or supplementation because they cannot be endogenously synthesized from precursor amino acids.
We’re diving into details on one of the most widely consumed fitness supplements out there and whether they’re worth adding to your stack. Let’s talk about the BCAAs.
If you haven’t heard the buzz around BCAAs, in order to know why they’re beneficial, you need to know what they do. Functional proteins (i.e. the building blocks of your entire body) are composed of 20 amino acids. Of those 20 amino acids, 11 are non-essential or conditionally essential, meaning your body can produce them de novo. The remaining 9 are classified, as I said, as essential because they cannot be synthesized in the body and must come from external sources. But with respects to the BCAAs, they are the only three amino acids metabolized in skeletal muscle and comprise approximately one-third of all muscle protein . In muscle, these amino acids serve as both an important energy substrate during exercise and periods of stress, and also as a precursor for synthesis of other amino acids and proteins . Because of this, athletes supplement with the BCAAs to prevent muscle protein breakdown during prolonged exercise, as well as boost muscle protein synthesis post-workout.
A Quick History Lesson On BCAAS?
Like I just mentioned, the BCAAs serve as an important energy substrate in skeletal muscle during periods of intense physical activity or stress, which is why these amino acids were originally researched for their anabolic role in catabolic disease states.
However, an interesting thing that a lot of people aren’t aware of about the BCAAs is that they actually exert a pretty powerful effect on glutamine metabolism. If you’re not familiar with glutamine, it’s another amino acid that’s essential for the health of the gastrointestinal tract. Specifically, it’s required for the health of rapidly dividing cells, especially those of the gut and immune system . And while gut health probably isn’t something you associate with performance, it plays a major, yet indirect, role in both your physical performance and your recovery. It should go without saying that if you don’t have a healthy gut, you don’t have a healthy body and your athletic abilities are going to suffer.
But the reason why athletes and anyone looking to bulk up muscle mass gravitate towards the branched chain amino acids is because of their role in protein homeostasis in skeletal muscle . Older studies note that the concentration of leucine, one of the most potent anabolic amino acids, in muscle cells exhibited important roles in regulating muscle protein turnover; the higher the concentration of leucine, the less muscle protein breakdown that occurred . This was the beginning of the popularity of the BCAAs. In order for muscle protein synthesis to occur (i.e muscle growth and repair), all 20 amino acids must be present. Of those amino acids, leucine is the most potent regulator of MPS. And while you can easily obtain all essential amino acids from food, supplementing with pure BCAAs means greater substrate availability needed to support proper muscle growth and recovery.
So, why take a BCAA supplement? If you’re looking to cash in on maximum performance enhancement, these guys are it. They may not power you through a gruesome double training session, but they’re sure to stimulate MPS and accelerate your recovery for better performance in and out of the gym.
The Benefits of BCAA Supplements
While the BCAAs are touted as being a superstar for muscle growth, that’s not the only benefit you’ll get.
Enhances Muscle Growth
This one is your goldmine where the BCAAs are concerned. It’s what they’re known for and there’s the research to back them up. But while supplementing BCAAs and sitting back and relaxing isn’t going to get you jacked, they can go a long way to enhancing muscle protein synthesis.
For the most part, the benefit of BCAAs on muscle growth is due to their high concentration of leucine, the most potent anabolic hormone. But like I said earlier about the BCAAs being used as a fuel substrate, of the leucine taken up by muscle, approximately 40% is accumulated and enters the free amino acid pool, 20% is incorporated into proteins, and 40% is oxidized for fuel . As such, the branched chain amino acids can serve as metabolic fuel during periods of fasting or caloric restriction, which is why you see a lot of people knocking back BCAAs when they’re hitting the gym for ‘fasted’ cardio. And then we have alanine, which is synthesized de novo by muscle and becomes essential for hepatic gluconeogenesis (production of glucose from non-carbohydrate substrates); alanine is derived largely from the BCAA valine, so as expected, consuming BCAAs helps to stimulate muscle protein synthesis and inhibit protein degradation, thereby contributing to the regulation of muscle protein turnover .
Before I skip ahead of myself, I want to jump back to leucine for a minute. Of all the amino acids, leucine plays the biggest role in protein turnover because it stimulates MPS and inhibits protein degradation through various mechanisms involving the mammalian target of rapamycin (mTOR) pathway.
While the mechanism as to how it does this is complex and we’re not going to get into it, research suggests that the anabolic effects of the BCAAs are likely mediated through changes in signaling pathways controlling protein synthesis. So, the more leucine available for MPS after resistance training, the greater activation of mTOR, which eventually affects translation initiation and elongation of proteins [14, 3, 5]. And there you have it, muscle growth. Boom, muscle growth.
But keep in mind that just because the BCAAs can stimulate MPS doesn’t mean you can skimp on dietary protein in place of shakes all day long. Eating adequate animal or plant-based protein is still key to your health and optimal performance, and in no way should supplements ever replace a balanced diet. If you want to perform at the top, you have to eat to support it.
Accelerate Recovery and Reduce Post-Workout Muscle Soreness
We all know that exercise causes damage to muscles. And the repair process that happens afterwards is what causes muscles to grow both in size and in strength. If you’ve gone through a few days of intense training, maybe even doubles, you’ve probably paid for it afterwards in the form of pain with every movement. This is what we call delayed onset muscle soreness, or DOMS for short. While the mechanism behind why DOMS happens isn’t understood, research suggests that it could be a combination of lactic acid accumulation, muscle spasms, connective tissue damage, muscle damage, inflammation, and the enzyme efflux . DOMS can have a pretty hefty impact on your performance by impairing joint range of motion, shock attenuation, and peak torque, but also muscle sequencing and recruitment patterns, which means that muscle ligaments and tendons are subject to greater stress, further contributing to the problem.
But that’s where BCAAs come into the picture.
BCAAS are particularly useful for people who go hard in their training, but forget about the recovery aspect (which I definitely don’t advise). Because poor recovery practices usually mean that muscle damage compiles over time to eventually become chronic, what you’re using for recovery supplements becomes a make-or-break kind of deal.
A good chunk of research has shown that amino acid supplementation (or obtained through diet) have potential as an effective intervention for enhancing muscle recovery by reducing protein degradation and/or muscle enzyme release, decreasing skeletal muscle damage in response to resistance training, reducing muscle soreness, mitigating central fatigue, and accelerating muscle recovery post-exercise .
- Decreases muscle soreness 48- and 72-hours post-exercise (enhanced glutamine production from BCAA degradation)
- Reduces serum creatine kinase (CK)
- Attenuates creatine kinase (CK) efflux
- Decreases residual muscle soreness
- Improves recovery of muscle function
The last thing you want during training is for fatigue to kick in. Your strength suffers, your power suffers, and your overall performance plummets. But adding in BCAAs to your pre- or intra-workout stack can help mitigate the onset of central fatigue during exertion.
Research suggests that certain amino acids may be involved in both energy production, as well as reducing accumulation of fatigue-inducing compounds, including 5-HT (serotonin), lactate, and ammonia during strenuous exercise. One study in specific looks at the impact of BCAA supplements on markers of fatigue and found that levels of serotonin, CK, and lactate dehydrogenase (LDH) were all lower in the group consuming the amino acids .
Another mechanism by which BCAAs may mitigate fatigue is through the serotonin pathways. By altering brain concentrations of 5-hydroxytryptamine (5-HT) that induce fatigue, we can prevent fatigue from setting in. Here’s how. Tryptophan, the precursor amino acid to 5-HT, is able to cross the blood-brain barrier (BBB) and forms the rate limiting step involved in 5-HT synthesis, which is a major regulator of perceived and experienced fatigue. However, studies have shown that plasma ratios of free tryptophan to BCAAs increase during physical activity to preferentially take up tryptophan, which ultimately increases levels of 5-HT and thus fatigue . But here’s the thing. All of these amino acids use the same transport proteins to cross the BBB and it’s kind of like a battle of the bigger amino acid; because tryptophan is small, larger amino acids like leucine, isoleucine, and valine essentially block tryptophan from binding and should theoretically reduce tryptophan uptake and the subsequent synthesis of 5-HT, thereby delaying onset of fatigue.
Prevent Muscle Loss
For people that regularly do fasted cardio or are lifting in a fasted state, BCAAs may be helpful for reducing muscle loss. Because you don’t want to enter a catabolic state at any point, BCAAs may prove useful for supplying energy to muscles and presenting muscle degradation. If there’s an abundance of essential amino acids available, the rate of MPS exceeds that of breakdown to maintain an anabolic state . In the postabsorptive (fasted) state, however, plasma EAA levels fall because they’re no longer being absorbed, which means that they’re not being taken up by muscle but rather released by muscle into plasma . This catabolic state enables continued availability of EAAs for other tissues to maintain a steady rate of protein synthesis at the expense of muscle protein.
This is exactly what we want to avoid.
Essentially, what the BCAAs do is reduce muscle protein breakdown by decreasing the activity of the degradation pathway, but also by decreasing the expression of several complexes involved in protein breakdown. So, if we revisit the initial equation with BCAAs on muscle growth, it’s obvious that when you stimulate muscle protein synthesis through supplementing exogenous essential amino acids, MPS exceeds breakdown and we remain in an anabolic state.
What To Look for in a BCAA Supplement
On top of that, you also want to look for a BCAA that offers the correct ratios of amino acids. Because leucine is king when it comes to stimulating MPS, you want a 2:1:1 ratio of leucine to valine and isoleucine. While some products will advertise that their ratios are 5:1:1 in favour of leucine, or even 10:1:1, it’s logical to assume that you’ll get 5x better results. But hear me out first before you go spending your hard earned cash on an ineffective product.
While it also may seem reasonable to just supplement leucine if it has the biggest effects, researchers at Baylor University administered college-aged men either a leucine supplement, a 2:1:1 BCAA supplement, or a placebo before and after lower extremity resistance exercise  Results showed that while leucine alone increased MPS after the workout better than the placebo did, incorporating the other two BCAAs (isoleucine and valine) may contribute to greater activation states of 4E-BP1 above and beyond what leucine alone is capable of.
So, if you want a good BCAA supplement, forego the single amino acids and forego the mega-doses of lysine for a 2:1:1 ratio providing at least 1 gram of isoleucine and 1 gram of valine per serving. However, if you’re looking for maximum gains, your best bet is to target at least 3 grams of leucine per serving, which is the minimum recommended amount required to optimize mTOR activation and maximize muscle protein synthesis.
I know we all love our flavoured supplements and I’m not denying that they taste amazing, but the thing with a lot of BCAAs is that they’re loaded with garbage. Any supplement in powdered form, unless you can find it in a pure form, generally contains some form of artificial sweetener (usually sucralose), several different colour dyes, and artificial flavours to go along with it.
A bit of sucralose here and there may not seem like such a bad thing, but the problem with artificial sweeteners is that over time they interfere with glucose and insulin function. Because of their sweet taste, consumption of artificial sweeteners triggers the release of insulin from pancreas, which leads to increased levels of insulin in blood eventually leading to decreased receptor activity and insulin resistance . Instead, you want to look for a BCAA that is free of artificial anything–sweeteners, colours, and flavours. look for a powdered supplement that uses natural sweeteners like stevia, and is free from any colouring or artificial flavouring.
So, if you’re looking for improved recovery, increased and timely muscle protein synthesis, as well as some extra performance benefits, BCAAs should be a staple in your stack as an athlete. Ensure that you’re choosing the cleanest, informed choice product that you can find, but pick yourself up some of this game-changing science and keep your body performing and recovering at it’s best.
Shea Pierre – Coach and Owner of Pierre’s Elite Performance
A Father & Loving Husband First, Sports Performance Coach, Former Professional Football Player, Entrepreneur and Motivator. Shea went from training athletes in his basement, to being head college strength and condition coach to be the head strength and conditioning coach of the Toronto Argonauts. He has now spread his knowledge to 50,000+ elite athletes worldwide and continues to be a go-to strength coach for professional athletes.
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