By now, you must have heard that BCAAs (branched-chain amino acids) ?

They can help you build muscle, limit fatigue, burn more fat, and reduce DOMS (delayed onset muscle soreness). Given how well the supplement industry markets them, you might even already have a bottle of BCAA powder stashed away in your gym bag right now. They do come in so many fanciful citrus and fruit flavours, after all. I’ll be the first to admit that any random BCAAs would taste better than many of the protein powders available in the market.

But – here's the crucial question to ask: do BCAAs work? Do they provide unique fitness benefits over other protein drinks or foods, other than the fact that they're tasty? Let's find out.

What are BCAAs?

To understand what BCAAs are, you first need to grasp the concept of amino acids. Now, amino acids are the building blocks that makeup protein – your body puts them together like Legos to synthesize muscle.

While your body can make some amino acids from scratch (aka non-essential amino acids), you need to obtain others (essential amino acids) from food or supplements. So, these essential amino acids (EAAs) are the limiting factor in your body’s ability to build muscle.

Research shows that 3 (out of 9) of these EAAs are particularly useful at increasing protein synthesis and can, therefore, be viewed as the more crucial amino acids for muscle growth. Guess which 3 amino acids these are? Well, yes – the exact ones found in BCAAs: leucine, isoleucine, and valine.

Okay, so if these EAAs have potent anabolic effects, BCAAs must be useful as a supplementation, right? Well, not so fast.

Tell me – do BCAAs work?

Do BCAAs boost muscle protein synthesis?

Here’s the truth: amino acids don’t work in isolation. You can’t just take 3 amino acids that show anabolic effects, put them together, and expect that they’re all that’s needed for muscle synthesis. Unless, of course, you’re the fitness supplement industry that only cares about the bottom line.

See, that's not how your body works. Your body needs complete forms of protein (all 9 EAAs) to achieve muscle protein synthesis, – not just the 3 found in BCAAs. If you're guzzling BCAAs like it's water, yes, of course, your body will be in excess of the 3 EAAs that show the most benefit in muscle synthesis. But does that mean that you'll be necessarily experiencing more significant muscle growth? No. That's because then, the other 6 EAAs becomes the rate-limiting factor. You have to consume enough of those to stimulate anabolic growth.

So when you think about it carefully, BCAAs don’t provide any benefit over other protein sources that have all 9 EAAs such as meat, fish, dairy products, and eggs.

Do BCAAs help with performance?

If you’re now trying to justify holding on to your BCAAs, I understand. They are pretty expensive. So, should you keep your BCAAs around in hopes that they’ll help with your training performance?

Unfortunately, several studies have failed to show a demonstrable, beneficial impact of BCAA supplementation on performance. What about mental performance, then? Well, few studies have examined the relationship between BCAA supplementation and improvements in mental performance. Some studies have found an improvement in mental performance when BCAA is ingested, as compared to a placebo, but subsequent studies have failed to replicate such findings.

From the looks of it, there isn’t much conclusive evidence on the impact of BCCA’s on performance. So – not much reason for you to reorder that bottle of ‘Mango Madness’ powder.

Well, okay, but can BCAAs help with fasted cardio?

But wait, what if you’re taking BCAAs to help preserve muscle mass while doing fasted cardio? According to the nutrition label, BCAAs don’t contain any calories – right? If you’ve been paying attention to where this article has been going, you wouldn’t be surprised by the answer. BCAAs do contain calories. And they do create an insulin response which, by definition, takes you out of the fasted state!

Just like any other protein, BCAAs contain roughly 4 calories per gram, which is approximately 40 calories per 10 grams serving of BCAAs. The reason why some nutrition labels show BCAAs as '0 calories' has to do with FDA regulations; they don't see individual amino acids as containing calories. And as you know now, that isn't true. At all.

And besides, why are you doing fasted cardio? Researchhas shown that there’s no resulting difference in body composition between doing cardio fasted or after eating. Mind-blown? I know, me too. But it’s a life-changer. I now get on the treadmill without feeling like I’m dying of hunger.

Great, so BCAAs are useless?

For the most part, current scientific literature suggests that BCAAs are a waste of your money. Of course, BCAAs are essential to ingest daily, but many protein sources – such as your trusty meat and eggs – already provide BCAAs. Even better, they also give you the other 6 EAAs that work – synergistically – to help with muscle-building.

Honestly, the only case BCAAs may provide some benefit is if you’re someone who has a low dietary protein intake. So if you're a vegan, for example, BCAA supplementation can help promote muscle protein synthesis and increase muscle growth over time in this case. But again, you’d need to supplement with other protein sources to obtain the remaining 6 EAAs. As we’ve established previously, BCAAs, on their own, don’t do very much.

You'd be better off just sticking to the traditional protein powder.

Takeaway

If you've been shelling out money for bottles of BCAAs in hopes of enhanced muscle growth and performance, you may be feeling personally attacked and annoyed right now. I know I was when I first learnt that BCAAs were useless. Well, at least now, you know. That's hundreds of dollars saved!

Since you’ve read to the end of this article, you must be a fan of evidence-based training. If so, you’d love GymStreak – an AI-powered personal trainer app that relies on all the latest research to customize a workout plan suited for your fitness goals and needs.

Want more evidence-based content? Check out the rest of our blog posts. Rather listen? No worries, we've got you covered. Here’s our podcast channel, where we motivate you and give you answers to all your burning questions. Till the next time!

References

Apró, W., & Blomstrand, E. (2010). Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle. Acta Physiologica (Oxford, England), 200(3), 237–248. https://doi.org/10.1111/j.1748-1708.2010.02151.x

Churchward-Venne, T. A., Breen, L., Di Donato, D. M., Hector, A. J., Mitchell, C. J., Moore, D. R., Stellingwerff, T., Breuille, D., Offord, E. A., Baker, S. K., & Phillips, S. M. (2014). Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: A double-blind, randomized trial. The American Journal of Clinical Nutrition, 99(2), 276–286. https://doi.org/10.3945/ajcn.113.068775

Churchward-Venne, T. A., Burd, N. A., Mitchell, C. J., West, D. W. D., Philp, A., Marcotte, G. R., Baker, S. K., Baar, K., & Phillips, S. M. (2012). Supplementation of a suboptimal protein dose with leucine or essential amino acids: Effects on myofibrillar protein synthesis at rest and following resistance exercise in men. The Journal of Physiology, 590(11), 2751–2765. https://doi.org/10.1113/jphysiol.2012.228833

Nutrition: Can BCAA supplementation help sports performance? (2017, February 24). Peak Performance. https://www.peakendurancesport.com/nutrition-for-endurance-athletes/supplements/nutritional-supplements-bcaa-effect-sports-performance/

Schoenfeld, B. J., Aragon, A. A., Wilborn, C. D., Krieger, J. W., & Sonmez, G. T. (2014). Body composition changes associated with fasted versus non-fasted aerobic exercise. Journal of the International Society of Sports Nutrition, 11(1), 54. https://doi.org/10.1186/s12970-014-0054-7