BCAAs: Pump or Dump?

Introduction

For some reason unbeknownst to our team here at The MusclePhD, branched-chain amino acids (BCAAs) have really become a subject of hot debate in the fitness community. Just about every time we make or see a social media post about BCAAs, about 50% of the comments and/or reactions are extremely negative. “BCAAs are trash,” we’ll see. “Best way to use BCAAs? Throw them in the garbage LOL,” was another solid response. And finally, “BCAAs are pointless with a high protein diet.” This one might have the most merit to it when all conditions are optimal, so we’ll discuss it in more detail later.

When one looks at the subject of BCAAs from a single perspective, it’s very possible to develop these opinions. But open your mind up a little bit. Who are BCAAs trash for? Should everyone throw their BCAAs in the garbage? Let’s take a look into what exactly BCAAs are, how they might affect gains, how to use this information in your own life, and how to understand and respect BCAA use by others.

What Are BCAAs?

We’re not going to go too in depth into chemistry or biology here because, frankly, that’s outside the, “need to know,” scope of this piece. Branched-chain amino acids consist of 3 amino acids: leucine, isoleucine, and valine. All 3 BCAAs are considered essential amino acids in that you have to get them from your diet; your body cannot make its own BCAAs (33). Dietary proteins are the primary source of amino acids in your diet. Animal proteins typically have a complete amino acid profile in which they contain all of the essential and non-essential amino acids, while plant proteins are often incomplete, in which they are missing at least one essential amino acid (35). Whey protein has the highest BCAA content of any protein source which helps boost its popularity and efficacy as a protein supplement (18).

Muscle Protein Synthesis

Muscle mass is predicated on the balance of muscle protein synthesis and protein breakdown (36). Protein synthesis simply refers to the creation of new proteins that can help repair damaged proteins or proteins that can be used to support gains. Growth can only occur during times of positive protein balance, in which protein synthesis is occurring at a greater rate than protein breakdown – kind of like a 2 steps forward, 1 step back situation. Protein breakdown can still be beneficial, especially after exercise as this can represent the removal of damaged proteins following intense training (33). However, a negative protein balance will more than likely result in a loss of muscle mass, which can occur during periods of caloric restriction and/or insufficient protein intake.

Muscle protein synthesis ramps up following resistance training (34,36) and following consumption of protein-containing meals (40). Our muscles exhibit a unique term called, “plasticity,” in that they can respond to several different stimuli in different ways (31). This is why both ingestion of food and stress by way of intense training can cause increases in muscle protein synthesis (29).

One of the more common complaints we saw about BCAAs is that many seem to think BCAAs will have no effect on muscle protein synthesis. Is this really the case? Let’s check it out.

BCAAs and Effects on Muscle Protein Synthesis

Science has known since at least 1975 that BCAAs can influence both protein synthesis and protein breakdown (5). BCAA ingestion alone can stimulate the mTORC signaling pathway that eventually leads to an increase in muscle protein synthesis (39). It appears that leucine is the most important BCAA for this process, as leucine itself can act as a signal to initiate translation which ultimately leads to protein synthesis (21).

We see the importance of leucine when comparing different sources or intakes of protein. Science has defined a leucine, “threshold,” or, “trigger,” in which a specific amount of leucine must be ingested to maximally stimulate muscle protein synthesis. Whatever source can provide that amount the fastest will more than likely be the most effective at promoting muscle growth (4).

It’s easy to see the importance of leucine in studies that add extra leucine to subjects already consuming enough whey protein to hit the leucine threshold – there’s no additional benefit (22). In addition, one can simply equate plant protein sources with animal protein sources by consuming a greater amount of plant protein. This equalizes the leucine content between proteins which also equalizes the muscle protein synthesis response (19,33).

Now, it is worth noting that, while leucine seems to get all of the glory when it comes to protein synthesis, both isoleucine and valine can also play a role. There’s several enzymes and cellular signals that have to be activated in order for protein synthesis to take place, let alone be maximized. Consuming leucine by itself may not activate some of these key signals as much as taking all 3 BCAAs together (23,26). Leucine is still more than likely the most important BCAA when concerning protein synthesis, but taking BCAAs all together appears to be more effective than just leucine by itself.

Ultimately, BCAAs alone can absolutely increase muscle protein synthesis (17) and are a critical component of protein intake when considering the effect a protein source can have on gains (18). So with all of this information, what do BCAAs help with when concerning training?

BCAAs and Training

Seeing as how BCAAs can reduce protein breakdown, several studies have found that BCAAs can help reduce soreness following a workout and can accelerate the recovery process (9,15,16,30,37). BCAAs, especially leucine, may also promote satellite cell activation when taken in accordance with a hardcore training program (24). Satellite cell activation can promote gains through a unique pathway which is outside the scope of this article – you can learn more about it in our Muscle Memory article here.

BCAAs taken before and/or during a workout can also provide energy to muscle cells. Leucine specifically can be converted to ketoisocaproate (KIC) and is oxidized in the TCA cycle to provide energy. Increasing intracellular KIC levels can also promote oxidation of isoleucine and valine by way of activating a specific enzyme that breaks down these amino acids to further provide energy (1,12).

The strong influence that BCAAs have on muscle protein synthesis and protein breakdown has actually led to investigations seeking their effectiveness on Duchenne Muscular Dystrophy (8). Duchenne Muscular Dystrophy is a disease characterized by muscular wasting and body fat accumulation – both variables that BCAA ingestion can benefit as various other hormonal anabolic medications may still have negative impacts on body composition (8).

So we’re seeing a large amount of evidence supporting the use of BCAAs. Why is there still hate? Let’s go into what, “The Other Side,” would say on the issue.

The Devil’s Advocate

Now, there is certainly some evidence to show that BCAAs aren’t necessarily the holiest of supplements. While BCAAs do promote protein synthesis, the protein synthesis response is always going to be limited by the amount of total amino acids you have available in your blood (33). The easiest way to think of this is to imagine a construction site for a house. Having just the BCAAs present means you have the key materials to build, like concrete for a foundation, beams for a structure, etc. However, you need more total amino acids for things like bricks, insulation materials, or plumbing. BCAAs are a great start, but their efficacy can be limited by total amino acid availability.

The flip side of this scenario can also be seen when essential amino acids (EAAs) are taken without leucine. You can still get a small increase in protein synthesis, but with leucine is added back in, that increase is much greater (27). Leucine could almost be seen as the foreman for the construction site. If the foreman doesn’t show up, little to no work is going to get done.

For further proof, several studies have shown that adding additional amino acids to a leucine or BCAA dose can increase the protein synthesis response (3,34). In addition, a study comparing a 25g dose of whey protein to a 6.25g dose + additional leucine found that protein synthesis was increased in the 25g dosage, even though leucine was matched between interventions (6). This particular study really underscores the importance of total amino acids when considering muscle protein synthesis spikes. BCAA supplements can certainly ramp up protein synthesis, but without sufficient total amino acids, you’re not going to get a maximal response.

So the above is more than likely one reason why people hate on BCAAs. They could somewhat be considered an, “incomplete supplement,” in the fact that they can definitely help gains, but the best effect occurs when the total amino acid pool is sufficient. What about the people who say BCAA intake is pointless in a high protein diet?

BCAA Content of a High Protein Diet

Studies examining the effects of BCAAs on recovery typically use 24-30g of BCAAs per day (15,30). If we examine the average 180lb bodybuilder eating an optimal bodybuilding diet containing 180g of protein per day, how would their overall BCAA intake look before supplements? The average protein consists of 4.8% isoleucine, 7.8% leucine, and 6.2% valine by weight (10). Therefore, a bodybuilder consuming 180g of mixed proteins throughout the day ends up taking in about 8.64g of isoleucine, 14.04g of leucine, and 11.16g of valine for a total of 33.84g of BCAAs. AKA they’re already well over the 24-30g/day range assessed in studies.

However, how many normal people are actually able to get this much protein per day? It’s no problem for professional bodybuilders – it’s literally their job to eat, sleep, and train. But what about the rest of us? What about my wife, a registered nurse in a huge hospital working at least 12-hours at a time? Real people are the ones we’re trying to impact with this information, so let’s go over how you could supplement with BCAAs the right way.

Supplementing with BCAAs the Smart Way

Studies show that, while eating a protein-rich meal can increase protein synthesis, this effect only lasts for about 3-hours (40). Interestingly enough, total amino acid availability is still pretty high 3-hours after a meal, but protein synthesis still drops off. So what gives?

The availability of amino acids doesn’t necessarily determine the period of protein synthesis following a meal. This period is more so predicated on the cellular energy state of the muscle (40). Protein turnover accounts for about 25% of resting energy expenditure, so if the energy content of a muscle cell starts to run low, protein signaling will drop to conserve energy (38).

Like we mentioned in the BCAAs and exercise section, BCAAs can provide cellular energy. Taking leucine 2-hours after a meal has actually been shown to keep protein synthesis at maximum levels whereas not supplementing with leucine results in synthesis rates dropping back to baseline about 3-hours after a meal (40). This means that taking BCAAs between meals can help maintain maximal protein synthesis levels, even if you’re not taking them with other amino acids!

So how exactly is this information useful? Why not just take a protein shake instead? Well, there’s this extremely important factor called, “convenience.” Convenience is one of the most important variables that drives dietary decision making (2) and a large majority of supplement users utilize supplements simply because they’re convenient (32). So if we consider my nurse wife, working her butt off during a 12-hour shift with no time to even take a lunch break, what’s more useful for her? A protein shake or BCAAs?

Unless you’re an absolute psychopath, odds are you mix your protein shake in some form of milk and enjoy it cold. Where do you have to keep milk? In the refrigerator. Where’s the refrigerator at the hospital? In the employee break room. What does my wife rarely have time for? A break. However, most BCAA supplements mix just fine in water. This means she can leave her shaker cup at the nurse’s station and chug it about 3-hours after she gets to work to keep protein synthesis elevated. Her breakfast of eggs, toast, and bacon will only ramp protein synthesis up for so long, so having that BCAA shake 3-hours later can help keep her gains rolling during her busy work day.

Chugging your BCAA shake will also be more beneficial than sipping it since your goal is to maximize protein synthesis a few hours after a meal. If you just sip on your BCAAs over an hour or two, you’re never go to supply a large enough bolus of leucine to adequately hit the, “leucine threshold.” If you never hit this threshold, you’re going to consistently stay under maximum protein synthesis levels. In addition, the whole point of grabbing BCAAs between meals would be to supply muscle cells with energy – if you’re just sipping on BCAAs you’re probably not supplying energy at a fast enough rate to overcome the depletion rate of cellular energy. If there’s one important thing you learned in college, it’s chugging… BCAAs, that is.

When else could BCAA supplementation be important? Have you ever heard of a diet? What’s the most important thing people will tell you to consider when you hop on a diet? Energy balance – calories in vs calories out. Consuming carbohydrates 2-hours after a meal can also help ramp protein synthesis back up as carbs will provide muscle cells with energy (40). However, you would need about 10x the amount of carbohydrates compared to leucine to get this effect (40). Since ~3.5g of leucine is needed to maximize protein synthesis (19), you’d need about 35g of carbohydrates to get a similar effect between meals. Which, in turn, would easily add well over 100-calories to your, “between meals,” supplement. Repeat 2-3 times a day for a few weeks and you might actually gain a pound or two. Not exactly the goal of a diet, right? Plus, the most convenient form of carbohydrate for someone like my wife would be a sugary drink like Gatorade or even soda. We don’t have time to go down that road in this piece, but I think we can all generally agree that minimizing sugar intake is a smart practice.

One last smart way to supplement with BCAAs for busy individuals is to do so about 2-hours after your post-workout shake. Studies have shown that consuming protein shakes right before and after your workout is actually more effective for gains than consuming them in other times throughout the day (7). Taking BCAAs 2-hours after your shake, then, could boost this benefit even further by ramping protein synthesis back up. This is a great method for people on the go or even college students who work out in the morning. Maybe you train from 7-8am then immediately go to work or class. You can chug a protein shake on the way, but then what happens around 10-10:30 if you can’t grab lunch yet? Down your BCAAs and keep the gains rolling!

A big component of BCAA supplementation is convenience. If you don’t understand how important convenience is to some people then you have no room to bash others for taking BCAAs. I’m sure there are some who think they’re hardcore while walking around with a cooler packed with meals for every 3-hours but, frankly, that’s not everyone’s cup of tea. And most business executives would frown upon you for pulling out some stinky chicken and broccoli in the middle of a meeting.

Lastly, there are still some current issues with BCAAs that have come out of the non-exercise or applied sciences, so let’s go over those findings and how they might really relate to our side of the science.

Current Issues with BCAAs

Oddly enough, BCAAs have come under fire over the past few years as some researchers have started to blame insulin resistance and obesity on BCAA ingestion. This claim is founded on the fact that, in individuals who are insulin resistant, plasma BCAA levels are often elevated as well. However, this is simply a correlation between the two instances, not causation. If insulin resistance is an issue, then BCAA metabolism will be impaired and plasma BCAA levels will obviously be elevated (42). Elevated plasma BCAA levels are just a marker of insulin resistance, not a cause (13,42).

So what causes insulin resistance? It’s pretty simple. Being lazy (14) and being fat (20). Obesity and a sedentary lifestyle will both promote insulin resistance and impair BCAA metabolism, which leads to both higher levels of blood sugar and plasma BCAAs (42). The correlations some people come up with are pretty amazing. Many want to blame insulin resistance on so many things, but it’s literally just poor diet, inactivity, and being obese. Not BCAAs.

In addition, a recent review by Wolfe (2017) made claims that the resultant spike in protein synthesis from BCAA ingestion will cause breakdown of muscle tissue to provide sufficient amino acid substrate for this increase in protein synthesis (41). However, there are some issues with these claims. First of all, these claims are based off of an, “essay,” regarding starvation (read here). I doubt many bodybuilders or BCAA users are experiencing periods of starvation, so this situation doesn’t really pan out in real life. For normal individuals, there will always be sufficient amino acids in the blood to provide substrate – this will not have to be provided by muscle tissue.

This review also makes the claim that the spike in muscle protein synthesis from BCAA ingestion alone is not a large spike and is limited by the overall availability of amino acids in the blood (41) – which is certainly true. But why then, make the claim that BCAA ingestion will force breakdown of muscle tissue to provide amino acid substrate for protein synthesis? If the small spike in protein synthesis is limited by amino acid availability, muscle tissue would not be broken down to provide substrate. And if this were true, we would see BCAA ingestion increase the rate of protein breakdown – when in fact, the opposite is true. The entire review is a contradiction of itself.

Retaining muscle mass is important for survival and the body has several mechanisms through which it can avoid breaking down muscle tissue for energy. Unless you’re actually starving, I really don’t think you have to worry about this scenario. Consuming BCAAs between meals will spike protein synthesis and will use the remaining amino acids from the previous meal as substrate (40) – not your precious muscle tissue.

Conclusion

Both sides of the BCAA argument are presented in this piece but the real takeaway that’s important for both haters and supporters is the idea of convenience. Having your BCAAs between meals can help maintain high levels of protein synthesis and taking BCAAs around workouts can also improve recovery and reduce soreness. If you have no problem getting a full meal every 3-hours and get plenty of total daily protein, then yeah, you probably don’t need BCAAs. However, you should enjoy being the minority and should probably be the silent minority. Your situation doesn’t reflect the vast majority of people, many of whom could stand to benefit from BCAA supplementation. Just because a supplement may not be a necessary inclusion in your lifestyle doesn’t mean it can’t benefit someone else. So if you plan on throwing your BCAA tub in the trash due to comments on social media, maybe just offer it to your busiest pal. One man’s trash is another man’s treasure, right?

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