Of all the supplements out there marketed toward making gains and maximizing muscle hypertrophy, BCAAs are some of the most hyped. They’ve gained a huge reputation in the fitness community as a kind of super-supplement that can help you accelerate your muscle growth, drive recovery, and keep you energized, all while sparing the calories that come from a full whey protein supplement.
But BCAA supplements are not all they’re cracked up to be. To be fair, there are plenty of merits of BCAAs that explain why they’ve gained this reputation, but they’re also generally poorly understood. Truth be told, a BCAA supplement might not be giving you the muscle-maxing benefits you think it does, especially when you compare it to a complete protein like whey.
Read on to learn more about what BCAAs are, what the science says about BCAAs vs whey, and whether or not a BCAA supplement is necessary for getting to your goals (Spoiler alert: If you’re already getting enough protein, adding a BCAA supplement is totally unnecessary).
What are BCAAs?
BCAA stands for “branched-chain amino acids.” BCAAs get their name from their chemical structures which contain a “branched chain” of carbons, which you can see in the image below:
There are three different BCAAs, which include:
Together, the three BCAAs make up a large component of the total amino acid pool found in muscle proteins.
BCAA vs Protein: What’s the difference?
If you’re already working on building muscle and eating enough to complement your gym routine, you’re probably at least passingly familiar with how important protein is in your diet. In a nutshell: protein is one of the three macronutrients. Proteins have several important roles including helping repair tissue, forming important enzymes and hormones, as well as acting as “building blocks” for many different tissues and organs in your body, including your muscle.
Proteins are complex molecules that are made up of different combinations of individual amino acids. There are a total of 20 amino acids which make up thousands of different proteins. Your body can endogenously make 11 of these amino acids on its own. However, it can’t make the remaining 9 amino acids, which means that you need to get them from the foods that you eat instead. These 9 amino acids are therefore referred to as “essential amino acids” (EAA for short). Three of those essential amino acids are the BCAAs valine, leucine, and isoleucine.
If a food source is a “complete” protein source, this means that they contain all nine essential amino acids (whey protein is a good source of this). Meanwhile, an incomplete protein source will only have some of the EAAs.
So to sum this up: Amino acids, including the three BCAAs, are the “building blocks” of protein molecules, and those whole protein molecules then make up the structure of your muscle tissue.
Do BCAAs help build muscle?
The basic idea of muscle hypertrophy (aka building muscle!) is as follows: when you’re doing heavy resistance training, you cause small amounts of physical damage to your muscle tissue. In other words, you’re literally creating small tears in your muscles when you lift. In response, your immune system launches a response to heal the damage caused to the muscle. With the right nutrition, your body can begin synthesizing new muscle tissue to repair the damage, which results in thicker muscle fibers. This process is known as muscle protein synthesis.
Ultimately, over time and with enough training and nutrition, this leads to bigger, stronger muscles.
Now, onto the big question: are BCAAs really that miracle supplement that you need to maximize your muscle gain?
Well, there’s no question that BCAAs play a significant role in the structure of your muscle proteins. In fact, it’s estimated that the three BCAAs make up about 35-40% of the essential amino acids in your body’s overall protein, and somewhere between 14-18% of the essential amino acids in your muscle protein.
What’s more, the BCAAs are really important on a biochemical basis for spurring muscle protein synthesis (MPS). We mentioned earlier that your body needs the right nutrition to start MPS, and one of the most crucial tools is the BCAA leucine, which triggers the enzymes needed for this important reaction.
So yes, BCAAs can certainly help build muscle. But that isn’t the end of the story.
BCAA vs protein powder for muscle growth
Even though BCAAs are an important piece of the puzzle for muscle growth, this doesn’t mean that taking a BCAA supplement is any better than using a whey supplement. Here’s why.
Yes, BCAAs can definitely help increase muscle protein synthesis when taken post-workout, as illustrated in a 2017 study. But the same researchers also found that this response was almost 50% less than they saw in a previous study in which they used a dose of whey protein with a similar amount of BCAAs. They concluded that, in order to maximize MPS after resistance training, it may be more helpful to get the full range of essential amino acids -- which are found in complete protein sources like whey, not an isolated BCAA supplement.
This point was further illustrated in a review published in the International Journal Of Sport Nutrition And Exercise Metabolism, which ultimately concluded that taking a specific BCAA supplement in addition to adequate protein consumption from other sources yielded no additional benefits in terms of muscle hypertrophy.
And what about muscle recovery and soreness after a workout? A 2019 meta-analysis found that BCAA supplementation was linked to decreased instances of delayed onset muscle soreness (DOMS) post-workout. However, many of the studies included in this meta-analysis were not comparing BCAA supplements to whey/protein powder, but rather to a placebo. In other words, the studies compare taking a BCAA to taking nothing. Well of course, in this context, taking BCAAs is better than nothing. Ultimately, this means there isn’t much evidence to suggest that an isolated BCAA supplement is better than protein powder for muscle recovery.
In addition, there’s some research that actually suggests that this recovery effect isn’t dependent on BCAAs themselves, but just good nutrition in general! For example, some studies have found that BCAAs weren’t significantly more beneficial for muscle recovery than carbohydrates post-workout.
Some may argue that isolated amino acids can maximize muscle protein synthesis (MPS) to a greater degree than whole protein sources. When isolated from whole proteins, essential amino acids are more easily digestible than whole protein sources, which your body needs to break down first in order to use. The ingestion of EAAs have been shown to stimulate muscle protein synthesis in the elderly.
But that in and of itself is not great evidence that taking a BCAA vs whey protein or any other whole protein source is superior for building muscle. The same studies that suggest that EAAs are better for maximizing muscle protein synthesis are done under very specific circumstances: namely, they’re conducted in a fasted state, and their effects on MPS were measured only directly after ingestion and after 3.5 hours. This doesn’t account for anything else that happened during the day, which means that more research should really be done before drawing any conclusions. In other words, these studies are short-term and done under very specific conditions, like after a fast or post-exercise, and don’t reflect real-life circumstances over a 24-hour period.
Ultimately, there’s just no evidence that taking an isolated amino acid is better than using whole protein sources for the long term.
So, are BCAAs necessary?
Yes, they are. After all, they’re considered “essential” for a reason – your body doesn’t make them on its own, so you need to add them to your diet if you want to build muscle!
But this does not mean that BCAA supplements are necessary.
If you’re getting enough high-quality protein from whole foods or from protein powder like whey protein, then you’re already getting plenty of BCAAs. This also shows that, as long as you’re getting enough protein in general, you’re getting the amino acids you need to build muscle (hence part of the reason that we make such a big deal about high-quality protein sources in the first place!)
There are a few potentially useful, context-specific applications for BCAA supplementation. For example, if you’re someone who isn’t otherwise getting enough high-quality, complete protein in your diet, taking a BCAA or EAA supplement is probably better than nothing at all. Vegans may also benefit from using a BCAA or EAA supplement, since it’s hard to get complete protein sources from a plant-based diet.
But for someone who is resistance training and already eating a high protein diet, you won't see benefits from an additional isolated BCAA supplement. Instead, you’re better off investing in a high-quality whey protein powder to ensure that you’re getting enough of all the essential amino acids that your body needs for protein synthesis and building muscle.
The key takeaways on BCAA vs protein powder
Ultimately, there isn’t anything inherently bad about using an isolated BCAA supplement. It just likely won’t do a whole lot for your muscle growth - in fact, it might even be a waste of money.
Bottom line: if you're already hitting your daily protein targets, then taking BCAAs isn't going to make a difference. And if you aren’t already getting enough protein in your diet but are looking to maximize your physique in and out of the gym, a better strategy would be to supplement with a complete protein powder like whey.
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