What are BCAAs: Is It a Supplement Worth Taking?

Find out what BCAAs are and what they can do for you as a supplement.

What you’ll learn here

Table Of Contents

Just heard about a new supplement from a gym buddy and wondering “What are BCAAs?” You’re not alone.

As hardcore workouts like high-intensity interval training (HIIT) and spin classes gain cult followings, the use of workout supplements is no longer limited to elite athletes and bodybuilders. 

Instead, these supplements have become increasingly popular amongst regular fitness enthusiasts (like you and me), creating a booming multi-billion industry. 

Just think back to what you often see in the gym’s changing room. 

Chances are, you would have witnessed a handful of people consuming an array of post-workout concoctions – from pills and powders to a rainbow of strangely luminous drinks. And it’s not all just protein and creatine powders. 

It’s highly likely that you’ve also seen someone downing a cocktail of BCAAs (branched-chain amino acids) because he/she believes that it’s the secret to building muscle and strength. 

But is it really? I mean, other than smelling absolutely delicious, are BCAAs truly worth the money you spend on them? In other words, do they work, or are they just another over-hyped workout supplement?

Let’s explore in this article.  

What are BCAAs? How do they work?

Branch-chain amino acids are the building blocks of proteins.

If you’ve been paying attention, you’d know that BCAAs is an acronym for ‘branch-chain amino acids.’ Because I know you’re wondering: amino acids are small units that make up proteins. You can think of amino acids as individual Lego pieces. 

In addition to being the building blocks of proteins, amino acids also play a crucial role in molecule synthesis and enzyme activity in your body. 

Of the 20 different kinds of amino acids found in your body, only 9 are essential. That is – your body cannot synthesize these naturally and needs to get them from the foods you eat in your diet.

And there’s a key trio (of the 9) identified to help maintain muscle mass by promoting protein synthesis and suppressing protein breakdown: leucine, isoleucine, and valine (1):

  • Leucine: Can directly activate the signaling pathway in skeletal muscle, thereby stimulating protein synthesis (2). 
  • Isoleucine: Induces the uptake of glucose, the energy source for muscle contractions, into cells (i.e. helps you train harder and longer) (3).
  • Valine: Further research is still needed to determine valine’s role in a BCAA supplement. But is nonetheless thought to be useful in promoting protein synthesis and suppressing protein breakdown. 

Guessed it yet? Yep – BCAAs are made of these 3 amino acids. 

Why? Well, because of their functions. Theoretically speaking, it makes sense that if you were to increase your consumption of BCAAs, you can improve muscle growth and prevent muscle loss.

Minus the additional calories (from protein consumption) or logistical problems of preparing a meal. 

But does it really? 

Summary

  • BCAAs refer to the branched-chain essential amino acids – leucine, isoleucine, and valine.
  • These 3 essential amino acids have been identified as the key trio that helps maintain muscle mass. They do so by promoting protein synthesis and suppressing protein breakdown. 

Are BCAAs necessary?

To examine if BCAAs are truly worth your hard-earned money (i.e. necessary), we need to look at its claimed benefits with an objective, evidence-based magnifying lens. 

#1: Help increase muscle mass

Find out if BCAAs help with increasing muscle mass.

If you’re like most, this is probably one of the benefits of BCAAs you’re most interested in. Given that BCAAs not only promote protein synthesis but also reduce muscle breakdown, you’d think that this claim is at least true. 

Unfortunately, no. 

It seems that we’ve all forgotten something crucial. As it turns out, for muscle protein synthesis to take place, your body needs all 9 of the essential amino acids present – not just the 3 found in that raspberry burst (or any other flavor, really) BCAA shake (4, 5). 

Meaning that if you only increase your consumption of BCAAs, the limiting factor to your muscle protein synthesis is then the remaining 6 essential amino acids. 

Or, in other words, the BCAAs you’ve consumed can’t do much when taken alone. 

Logically speaking, this also means that you’d be better off eating/supplementing with a complete protein source instead. 

Truth about BCAAs and protein synthesis response

And research agrees. 

A 2008 study found that muscle protein synthesis was greater after whey protein supplementation compared to the same amount of essential acids in an isolated form (6). 

This finding is further validated by a 2017 study, which found that the resulting protein synthesis response from 5.6 grams of BCAAs post-workout was half that of what would be achieved with an equivalent dose of whey protein (7, 8). Ouch much?

Furthermore, if you were to nitpick at the studies that have shown a positive benefit of BCAAs on muscle mass, you’d quickly realize that many of them are flawed. How so?

Well, many of them involve subjects that didn’t eat enough protein in the first place (9). 

So, to show that a BCAA supplement could help mitigate the damage from an insufficient daily protein consumption isn’t exactly exciting. Wouldn’t you agree? 

If you’re wondering about optimum protein intake, here’s an article on how much protein you need for your goals.

Ultimately, when you strip away the fancy marketing speak and hype, you’ll realize that you could achieve the same levels of muscle protein synthesis through consuming/supplementing with complete protein sources. Which is cheaper, by the way. 

And if getting enough protein through your diet is a problem, you could consider meal prep to improve your daily nutrition intake. It’s not difficult to get started and can be adjusted to accommodate your lifestyle.

Summary

  • You need all 9 essential amino acids for protein synthesis – not just the 3 found in BCAAs.
  • The same levels (or more) of protein synthesis from BCAA supplementation can be achieved through consuming/supplementing with complete protein sources. 

#2: Reduce fatigue during exercise

Read through any BCAA supplement label, and you’ll come across the claim that it helps reduce physical and mental fatigue. In other words, it helps you train for longer and harder during your workout sessions. Perfect for achieving progressive overload and increasing training volume, right?

Studies have indeed shown that participants given BCAAs during exercise reported up to 15% less fatigue than those who were given a placebo (10, 11). 

But here’s something important to note. There have been more studies showing the opposite. And perhaps more importantly, that decreased fatigue did not translate into improvements in actual physical performance (12, 13, 14).

Be honest. What’s the use of feeling less fatigued if it doesn’t lead to improvements in performance? 

Besides, research also indicates that BCAAs may be more effective at reducing exercise fatigue in untrained individuals compared to trained ones (15). This means any benefit you enjoy (if any) would deteriorate over time. 

Psst: Want workout supplements that actually work at reducing fatigue and improving physical performance? Look no further than caffeine and creatine monohydrate. Because of how affordable and effective they are, you won’t regret investing in them. 

Here’s a guide on workout supplements that are worth taking.

Caffeine and creatine are proven supplements you should invest in.

I can’t say the same for BCAAs. More benefit-debunking below. 

Summary

The research on BCAA supplementation’s effect on fatigue is mixed. And worse, even when participants reported feeling less fatigued, it didn’t translate into actual improvements in physical performance. 

#3: Reduce muscle soreness

Because BCAAs lower blood levels of the enzymes creatine kinase and dehydrogenase, which are involved in muscle damage, BCAA supplementation is thought to be beneficial in helping your muscles feel less sore after exercise (16). 

However, it turns out that this effect is modest at best if you’re eating a diet adequate in protein (17). 

Besides, if you’re looking at evidence-based ways to manage muscle soreness, try active recovery. It is one of the simplest and most effective ways to recover from sore muscles at no extra cost. 

If you’re interested, here’s an article on what helps with sore muscles after workouts.

Summary

Eating a diet adequate in protein is going to help you prevent and alleviate muscle soreness just the same as supplementing with BCAAs.  

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#4: Lower blood sugar levels

Interestingly, one of the supposed benefits of BCAAs also includes ‘maintaining normal blood sugar levels.’

Honestly, it isn’t that big of a surprise. That’s because, as mentioned earlier, one of isoleucine’s functions is to cause your muscles to take in more glucose (aka sugar) from your blood. Thus – decreasing your blood sugar levels. 

This sounds good and all, but the truth is that effects seem to vary between participants. 

For example, a 2012 study gave participants with liver disease 12.5 grams of BCAAs a day. Blood sugar levels were only reduced for 10 participants, while 17 others experienced no effects. In other words, we can see large inter-individual differences (18).

Meaning that more rigorous studies need to be done before we can draw any strong conclusions.  Thus, BCAAs are not worth it if you’re looking to control your blood sugar levels with them.

Summary 

There are large inter-individual differences in the effect of BCAAs on blood sugar levels. More studies need to be conducted before we can draw any strong conclusions. 

#5: Enhance weight loss

BCAAs are not proven to help with weight loss.

I don’t know about you, but I remember my eyes lighting up when I first heard of this benefit. I’ll be real with you – losing weight is hard. So, like any other human being, it can be pretty hard to refuse a product that promises a weight-loss fix you can simply eat. 

And the evidence for BCAAs as a weight loss tool seems pretty solid. At first glance, that is.

Observational studies report that those consuming an average of 15 grams of BCAAs from their diet daily may have up to 30% lower risk of becoming overweight/obese than those consuming an average of 12 grams a day (19, 20). 

This finding is further bolstered by a couple of studies that showed enhanced weight loss with BCAAs compared to soy protein and whey protein supplementation (21, 22). 

However, you’ll soon realize that they don’t exactly tell you anything useful. That’s because they offer little additional information about the composition of the supplement and the diet which followed – both of which could have influenced the results. 

Ultimately, no matter how hard we wish for a quick weight-loss miracle, the only thing that’s been proven to work (again and again) is a calorie deficit. 

Eat fewer calories than your body burns, and you’ll lose weight. This is by no means easy, of course. Fortunately, there are useful tips for weight loss that you can try to help you adjust to maintaining a calorie deficit.

Summary 

Instead of hoping that BCAA supplementation will help you lose weight faster, realize that a consistent calorie deficit is what you really need. That’s the only thing proven, again and again, to help you lose weight. Not to mention, keep it off. 

#6: Preserve muscle mass during fasted training

This is probably one of the most hyped-up benefits of BCAAs. And it relates to fasted training – in other words, training in a fasted state. 

It’s commonly believed that because BCAAs have a smaller impact on insulin levels, BCAAs will allow you to remain in a fasted state while preserving your muscle mass. That’s why you’ll see many people happily taking pictures with their BCAAs while doing fasted training. 

And thinking that BCAAs are well-worth their money.

But honestly, they’ve forgotten something. Something crucial. Remember how your body needs all 9 essential amino acids for protein synthesis?

Well, guess where your body is going to source for the remaining 6 essential amino acids when you take BCAAs alone during fasted training? Yep – your muscle tissues. Meaning that your body will need to break down your muscle tissues for protein synthesis. Ouch. 

This is supported by recent research from the International Society of Sports Nutrition (23). According to the study, when BCAAs are taken in isolation, it actually:

  • Decreased protein synthesis
  • Increased protein breakdown
  • Interfered with the absorption of amino acids

I don’t know about you, but the above effects are definitely not what I’m looking for if I’m doing fasted training. Oh, and do you want to hear something funny? 

They contain calories and, as a result, break your fast 

What most people fail to realize is that BCAAs consumption takes you right out of the fasted state. Just because its insulin response is smaller than that of whey protein, for example, doesn’t mean that there isn’t any insulin response. 

And that’s because BCAAs do contain calories. Just like any other protein source, they contain roughly 4 calories per gram, which equates to 40 calories for a typical 10 grams serving. 

I know what you’re thinking: “So, why does my BCAA supplement say it’s zero calories?”

You can trace this back to FDA regulations. Individual amino acids aren’t thought to contain calories. 

But, as you know now, that’s not true. 

So, does this then mean you’ll have to resign yourself to the fate of muscle breakdown during fasted training? 

Not exactly. That’s because fasted training doesn’t seem to cause muscle loss in the first place if you’re hitting your daily protein intake requirement (24). That said, if you do notice a significant decrease in strength during training, you could consider eating a carb-rich meal before your workout – instead of BCAAs. 

You’ll break your fast. But you’d have broken your fast with BCAAs anyway. Also, just so you know, fasted training doesn’t give you better results (be it muscle-building or fat loss) (25). 

My question, therefore, is: “Why are you training fasted in the first place?” If it’s anything other than because it fits right into your schedule or intermittent fasting needs, then don’t bother. The hunger will not be worth it. 

And if you’re curious about what carbs and protein, check out this article on macronutrients and micronutrients.

Summary 

  • When taken in isolation, BCAAs decreased protein synthesis, increased protein breakdown, and interfered with the absorption of amino acids.
  • Despite popular beliefs, BCAAs do contain calories and, as a result, will break your fast. That’s regardless of its ‘lower insulin response.’ 
  • Training fasted offers you no real benefits. Only do it if it fits your schedule or you truly enjoy it. 

BCAAs side effects

They are generally safe for healthy individuals.

By now, you must have gotten a pretty clear idea of whether BCAAs are truly worth it. And the answer should be a resounding no.

Regardless, taking BCAAs is generally safe and without side effects for many people. 

Studies on the safe upper intake levels of BCAA supplementation are rare, but research reports that total BCAAs intake between 15 to 35 grams a day seems generally safe (26, 27). 

That said, if you’re suffering from Gehrig’s disease, you should stay away from BCAA supplementation (28). The same applies to individuals with a rare congenital disorder known as maple syrup urine disease (29). 

Summary

BCAA supplementation is generally safe and without side effects, even at safe upper intake levels. That is unless you suffer from Gehrig’s disease or maple syrup urine disease. 

Are BCAAs worth it? 

If you’ve read this far, I’m pretty sure that you’ve come to the conclusion that the advice for BCAA supplementation is as misguided as many of the women’s fitness myths out there.

It’s like asking women to only lift 2 kg dumbbells so we don’t get ‘too bulky’ or that you should only do cardio for fat loss. 

I wouldn’t disagree. Women can and should lift heavy. And as we know, both cardio and resistance training have a part to play in fat loss. 

But here’s a caveat. 

BCAAs can be immensely helpful for vegans or vegetarians who struggle to consume adequate amounts of the BCAAs (leucine, isoleucine, and valine) through their diet.

That’s because the majority of vegan/vegetarian food options are incomplete protein sources (30, 31). Learn about complete and incomplete protein sources and why it matters.

Regardless, vegans should definitely still take BCAAs with another protein source to avoid the drawbacks mentioned earlier (i.e. not take BCAAs alone). As for others, well, I think the conclusion is pretty clear: BCAAs are not worth it.

Save your money on BCAAs. It can be better spent on complete protein sources and/or different types of protein powder.

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