Ep. #314: What Can BCAAs Actually Do For You? (According to Science)

Mike : [00:00:30] Hello and good day to you. This is Mike Matthews from Muscle For Life and Legion Athletics. Back with another episode of the Muscle For Life podcast and this time around I interview the co-founder and former lead researcher and writer of examine.com. Somebody who knows more about supplementation than anybody I will ever meet again in my life, Kurtis Frank, on the truth about branched-chain amino acids, BCAAs.

Now, for years BCAAs have been an absolute staple supplement in the bodybuilding scene. If you’ve ever seen a muscle boy or girl in the gym lugging around a gallon of fluorescent liquid, chances are it is water and BCAAs because supposedly these little guys can help us build muscle faster when we are bulking and retain more muscle when we’re cutting and there are a number of studies out there that are often cited to support such claims. And if you take that research at face value, it all seems to add up.

And there you go, you have a best-selling supplement on your hands. Ironically, the number one requested product over at Legion Athletics is BCAAs and it’s also a product that we refuse to sell. Why? Well, when you roll up your sleeves and you take a closer look at the research and the weight of the evidence on the whole, a very different picture emerges. As you will discover in this podcast, BCAAs unfortunately, don’t really have much to offer beyond making your water tastier. Unless you are an athlete, if you are, there is one legitimate use for BCAAs that might be relevant to you. But if you’re not, you’re wasting your money.

Mike : [00:04:15] Kurtis, thanks for coming back on the show once again to give us supplement wisdoms. And today’s discussion is something that – it’s good that we’re putting more content out, and maybe worth actually considering doing a bit more writing on BCAAs, because it is the number one product that we are asked to create.

“When are you going to do BCAAs? When you do BCAAs?” And the answer has always been: probably never, because there doesn’t seem to be any good reason for you, Mr. or Mrs. Average Gym Goer, to supplement with BCAAs. It’s not going to help you gain muscle faster. I mean, unless you just like tasty water. And that’s not a very good sales pitch because, well, it’s just not.

It’s funny though, actually a number of people write back and just say, “okay, even if that’s true and there are no real benefits to supplement BCAAs, I do like tasty water. I would buy them from you. I’m gonna buy them regardless and I’d buy them from you.” But, you know, just recently, right?

You were looking into: could we swing a BCAA product of some type for any reason that would be, you know, legitimate and it would make for a good sales pitch, a convincing sales pitch, an honest sales pitch, and obviously you came back negative. And I guess that’s kind of segway into today’s discussion – why? And for people listening, just to answer that question of what BCAAs are, why are people using them, and what can they do, what can they not do and so forth.

Kurtis : [00:05:55] All right. So BCAAs the branched-chain amino acids, just to get obvious out of the way, they have three amino acids that have branched chains. The other amino acids are pretty much straight lines, these ones are all bent. And they were grouped together specifically for that purpose, just structural. The three BCAAs, leucine, isoleucine, and valine do different things in the body and truth be told we don’t know anything about valine.

It’s just nobody really wants to research it. But leucine is the primary one that stimulates muscle protein synthesis. And this led to BCAAs being marketed initially because it was claimed that they could build as much muscle as protein, but because you’re taking in less amino acids overall, it’s less calories. Then this, you know, fueled the consumption of BCAAs, it was later found out that this was not the case, you needed all essential amino acids to sufficiently build muscle. 

Mike : [00:06:53] Shouldn’t that have been obvious from the ontset?

Kurtis : [00:06:56] It was not necessarily obvious from the onset because there are stores of amino acids in the body. Mostly the intestines and liver. So it is thought that if you could just tell the muscle to start building, it will start taking amino acids from the liver, intestines, and then those stores would be replenished next time you eat food. But it seems that it’s not so simple, you can’t just take amino acids from the liver because it’s incredibly greedy. So it needs a surplus of most amino acids, probably all the essential ones in the blood when you stimulate the muscles.

Mike : [00:07:31] So in a sense, those are essential amino acid stores. I know that’s not the correct term, but in a metaphorical sense, the body holds onto those because they are more important than more muscle.

Kurtis : [00:07:46] Pretty much. Like, you have to feed your immune cells. The intestinal cells have a turnover rate that is measured in minutes, so you need to create more intestinal cells. The liver just needs a large store for amino acids because it handles any insult and needs to be prepared for those insults. And like glutamine itself is a huge buffer that regulates blood acidity. So there’s so many more important things in the body than building muscle, because to the body, building muscle does not, in the short term, regulate survival.

Mike : [00:08:18] Right. I mean, obviously, the total amount of lean mass is correlated with just all cause mortality. But yeah, being more jacked doesn’t necessarily mean you survive better so long as you don’t have a very low amount of lean mass, right?

Kurtis : [00:08:36] Yeah, but again, it’s more of a long-term thing. When organs get greedy, it’s more of an adaptation over time for acute stressors. Like the intestines and liver will only release their amino acids for the muscle, I believe in situations of trauma involving like a weapon wound, where you’re actually bleeding out or third-degree burns, which is why there were studies on glutamine shown increased muscle growth, because that was a situation of which the other stores in the body would give up their glutamine.

Mike : [00:09:09] I see.

Kurtis : [00:09:11] But BCAAs got caught up in the hype where they thought it could build muscle and it turns out that they cannot build muscle by themselves. But at the same time, BCAAs were just so cheap to produce and I guess they were – I guess a culture formed around them pretty early on. They’ve stuck in the market for – ever since then, to be honest, it’s one of the most popular supplements.

Mike : [00:09:32] I mean, yeah, it was one of those tipping point products, right? Because it hit on a big benefit that people wanted, they were inexpensive to produce, so that means that there’s a lot of money that could be spent on the marketing of them. And also, you can make them taste delicious, even though they taste terrible by themselves with artificial sweeteners and artificial flavoring, you can make pretty much anything taste really good and so it’s just that perfect storm of factors that made for a real kind of runaway success.

Kurtis : [00:10:07] Yes, like a perfect cash cow product.

Mike : [00:10:10] Exactly.

Kurtis : [00:10:11] People are always going to buy it regardless of what you say, so if you want to sell it, at least try to find one or two niches where it actually works. But then we’ve gotten to the discoveries where the signaling for muscle growth was attributable to leucine solely. So if you wanted to stimulate muscle growth, you would just get leucine. You don’t need isoleucine or valine. So it’s cheaper, you could take smaller pills if you’re going the pill route.

Mike : [00:10:39] Doesn’t isoleucine stimulate protein synthesis weakly, very weakly, or no?

Kurtis : [00:10:46] Very weakly, but so weakly that I would say it’s inconsequential compared to leucine. Isoleucine is pretty good at high doses to increase the uptake of glucose into muscle cells, but it’s high dose. I believe the studies use 10 to 11 grams of isoleucine alone. So there is a potential for isoleucine in high doses to be used as a post workout to increase glucose uptake into muscles. But I believe isoleucine if you take it away from BCAAs and pump up the dose, it starts to get really expensive at that point.

Mike : [00:11:25] Yeah, I’m sure. Just because if you’re isolating it even further, that’s how things get very expensive.

Kurtis : [00:11:32] Yeah, but leucine at those doses is not expensive.

Mike : [00:11:35] Right.

Kurtis : [00:11:36] But so leucine took that crown. And then for actually building muscle, the crown was, ever since the initial discovery, always with protein itself. So you have BCAA in a little area where it can do both those things less good than either of the initial ones. So you choose A which is protein or you choose B which is leucine.

Then in the middle, BCAA’s like, “well, we suck at that and we suck at that. What do we do?” Like, literally, for a long time, the only reason BCAAs were still sold were because they were on the market and people were buying them and you just want to keep the money coming in.

Mike : [00:12:16] Yeah, I mean in the office, that’s what some people were saying. Like, “yeah, we don’t have to lie to sell them, but so many people ask for them, so many people buy them, so many people say that they’re going to keep buying them simply because they like them.” I’ve also heard some people say that when they’re cutting, they feel like it helps stave off hunger and cravings, at least hunger to a certain degree. And so in the office again, people are like, “I mean, can’t we just make them and not claim they’re going to do anything that they’re not going to do.” But I still think that that’s just such a weak product.

Kurtis : [00:12:53] It starts a bad precedent.

Mike : [00:12:55] Yeah, and then what does that sales page look like? What’s the pitch? Tasty water?

Kurtis : [00:13:00] “BCAAS, you’re going to buy them. This one’s great.”

Mike : [00:13:03]  Yeah, that’s about it. And I feel like that goes against the brand …

Kurtis : [00:13:07] It’s like a satire sales page.

Mike : [00:13:08] Yeah I know. If we were making joke supplement websites, joke supplement companies, that would be one of the products.

Kurtis : [00:13:18] “BCAAS, they don’t do much, but we have 25 flavors to choose from. Those competitors over there have 3.” 

Mike : [00:13:25] “Buy now!”

Kurtis : [00:13:26] “That’s a low number. Cookies and cream with peach. No one buys it, but it just adds to the list!”

Mike : [00:13:32] [Laughing] That’s how popular they are.

Kurtis : [00:13:36] Yeah pretty much. But like, so because Legion is a whole premium sports company, we can only sell stuff that has an effect, which is why I tried to look into a legitimate effect of BCAAs. And I technically did find one, but it’s not something most people would, you know, use it for.

Because BCAAs seem to have a role in preventing central fatigue, central just refers to the brain, in a way that is probably due to the – I’d say, I wouldn’t like give a little nod to valine here, but the truth is, the mechanisms of how BCAAs prevent fatigue is just due to the fact that they’re literally branched.

Mike : [00:14:24] You want to explain that?

Kurtis : [00:14:26] Yeah, I was just trying to figure out a segway, so thanks for that. When it comes to … not sarcastically a segway, you were my segway.

Mike : [00:14:34] [Laughing] That’s all I’m here for. I’m just here for segways.

Kurtis : [00:14:38] I thought I was being unnecessarily sassy. [Laughing] So when you’re working out, you just have muscle breakdown and amino acids go into your blood and they just float around, some go to the brain, realize, “we have nothing to do here,” so they just leave, go to the kidneys, and eventually get processed out.

But the more you work out, the more amino acids go in your blood and ammonia builds up and this does lead to fatigue. But another thing that happens is tryptophan, the turkey amino acid, as many people know it by, that also produces serotonin and thus melatonin can go into the brain and start to accumulate.

And when it accumulates in the brain that is strongly associated with not just fatigue, but also fatigue related to heat stress. I do not know why it’s related to heat stress, but it seems that this type of fatigue happens faster in hot environments.

Mike : [00:15:31] I can attest to that, having grown up in Florida and then now having lived in Virginia for a couple of years where it gets hot, but it’s not Florida hot. It doesn’t suck the life out of you like the Florida heat does.

Kurtis : [00:15:43] Yeah. There’s like a certain fatigue unique to heat. So tryptophan does this because tryptophan turns into neurotransmitters, but it’s also a large neutral in charge amino acid. There’s actually a transporter into the brain. So the door of which it goes through is called the large neutral amino acid transporter, very aptly named.

It just looks for large neutral amino acids. Tryptophan is one of them, but not the only one. If you pump a lot of BCAAs into the system, they’re also pretty large and neutral and they just kind of float around the body. They sort of clog up this transporter a little bit. So the tryptophan that would normally go into your brain just hangs around the periphery.

Mike : [00:16:24] Interesting.

Kurtis : [00:16:25] It delays the buildup of tryptophan in the brain, not perfectly, because eventually the BCAA is just going to leave or the BCAAs just get eliminated. But by delaying this, it can delay, prolong fatigue with specific reference to a heat. But also more like when you get fatigued and your finite motor control goes down a bit.

That’s also fatigue that BCAAs can prevent a little bit. So not so much Crossfit, not so much repetitive running where you just do one repetitive motion all the time, but more so in highly technical sports like tennis or badminton. Those are the ones where BCAAs supplementation can really help.

Mike : [00:17:09] Interesting. Interesting. So it’s similar to synephrine or yohimbine effects on fat cells where they clog up the alpha receptors and fat cells, right? Which allows them to be mobilized more easily?

Mike : [00:17:23] Sort of. I don’t think BCAAs literally block the transporter.

Mike : [00:17:27] Oh, okay.

Kurtis : [00:17:27] They’re just kind of slow. Because the transporter will accept whatever is there. And if it’s only tryptophan, only tryptophan is going to go through. But if it’s BCAAs, they’re going to have to take turns. It’s not like when tryptophan gets into the brain, it just always stays there, there is a chance for it to get as well. So as long as the ratio is kind of balanced, then the ratio and the brain will be kind of balanced and not as fatigue prone, one could say.

Mike : [00:17:52] That makes sense. Yeah, because I guess it’s a transporter, not a receptor, there’s a difference there. I was thinking, you know, it could be like caffeine and adenosine receptors, but again, that’s different. If it’s a transporter, yeah, it just keeps them busy, basically.

Kurtis : [00:18:04] Yeah. But the main thing that I want to get into and this is like the part where I can say BCAAs actually work. Because for the longest time, BCAAs, despite these mechanisms, did not show much strength. Like, they technically delayed fatigue, but it was like you got one extra swing in a tennis match. Like, “oh, no, that just makes such a difference.” [Laughing] It doesn’t. This is because what I mentioned earlier, how amino acids are breakdown products, ammonia is produced and ammonia causes fatigue.

BCAAs themselves will produce ammonia. So they cause fatigue in a way. BCAAs for the purpose of reducing fatigue, shoot themselves in their own feet. Which is why I wrote this article for Muscle For Life recently, BCAAs Paired with Citrulline. Because citrulline through – I think it’s called the urea cycle, I don’t know how I forgot that – can help reduce ammonia build up in the blood.

So BCAAs do their unique effect on preventing fatigue. There is the natural side effect of increasing ammonia, which would normally shoot themselves in the foot. Then citrulline takes care of the ammonia issues and allows BCAAs to actually shine without being apparent. And the studies that I went over on this article, there’s one looking at elite tennis players where they’re basically put through a few simulated matches just to make them fatigue and then they just shot tennis balls at them and said, in a very suggestive manner, “go until you fall.”

And in the last stages of fatigue, citrulline seemed to stave off half of the fatigue that the placebo group experienced. The BCAAs citrulline curveball, I should say. So, yes, there actually does seem to be a specific promise for BCAAs, but it may require citrulline or potentially eflornithine in combination with BCAAs to truly shine. And again, it only shines in like, cognitively heavy, fatigue-prone sports. So it’s not something everyone does.

Mike : [00:20:19] Yeah. It would be more of an enduring supplement. Which is something you’ve worked on, but we’ve shelved for now because we don’t have very many heavy endurance athletes. That’s not exactly our target market and I’m not sure what that market is like or how difficult it is to break into. But it would sound like BCAAs would have a better place in a supplement like that than anything having to do with building muscle or losing fat.

Which, of course, makes even less sense, but people hear things so I’d say it’s 80 to 90 percent of the reasons why people that we hear from are taking BCAAs are leaning more to muscle. And if it’s fat loss-related, it’s usually muscle preservation. They think that if they drink BCAAs all day, they’re going to lose less muscle when they cut or maybe even, you know, gain more muscle when they cut. But some people also think that it helps some lose fat faster.

Kurtis : [00:21:18] Well, they can do whatever they want, but they’re just going to be wasting money. There is no evidence that I know of to suggest that BCAAs have a direct role in fat loss. And for an indirect role through the muscles, again, there’s no good evidence of that. It’s basically a “what if” theory that leads to an extra like 30 bucks a month minimum. There are plenty of cool “what if” theories out there, just select one that has a bit of promise.

Mike : [00:23:17] And what are your thoughts about, this is very common, why people might be – well, there might be some legitimacy in terms of what they are experiencing phenomenologically, and that is reduced hunger. Do you think it’s just due to drinking something sweet or? This is when cutting. You know, this is again, something that I hear often from people that accept that, yeah, okay, fine.

It probably doesn’t have any muscle-related benefits really. But when I’m hungry and I’m cutting and I drink this BCAAs…” I mean, who knows, it could be as simple as: these people don’t drink much water or much liquid at all and then when they’re cutting, because they’re drinking BCAAs, it increases their water intake and that alone could increase general satiety, right?

Kurtis : [00:24:03] I’m actually thinking there might be some weird neurotransmitter shenanigans that I can’t explain. Because there are a lot of serotonin receptors in the gut and activating them will reduce hunger. The large neutral amino acids like tryptophan are closely linked to serotonin metabolism.

So if you are able to activate serotonin receptors in the gut, you can reduce hunger. Now, when you mentioned that I was trying to think about all the research that’s on BCAAs and serotonin, but I haven’t really seen any. This may be a question that people haven’t really investigated much. But there is potential for weird shenanigans with serotonin receptors.

Mike : [00:24:41] I see.

Kurtis : [00:24:41] I can’t completely eliminate that. But beyond that, like just having water or just like, having something in your mouth, because if something’s in your mouth, you’re not thinking about putting something else in it at that exact same time.

Mike : [00:24:53] Right.

Kurtis : [00:24:54] You coil the oral fixation, so to speak. That could also be a good reason.

Mike : [00:24:58] Right. And I mean, based on what you’re saying regarding ammonia buildup, it sounds like it’s counterproductive for fitness people to be drinking BCAAs all day.

Kurtis : [00:25:10] If they are light …

Mike : [00:25:10] I mean, let’s say you work out after work and you’ve been drinking BCAAs for eight or nine hours or something, and you go do a workout.

Kurtis : [00:25:18] I think it might be a bit of a downside. Well, definitely, if you have kidney issues, because then the ammonia can’t get processed as well. It might be cleared by time, but if people do drink BCAAs throughout the workday and they find that they can never get a good workout in, it could be useful to just go off to BCAAs for a few days, see how you feel. Because while I don’t think it’s a red flag at all, it’s definitely possible that excessive BCAA consumption could just screw up your workout.

Mike : [00:25:48] Makes sense.

Kurtis : [00:25:49] It’s something for people to test out.

Mike : [00:25:50] Sure. Makes sense. What about, we were talking about this before we started recording, a theory that has been bouncing around online that BCAAs may stunt muscle gain as opposed to augment it.

Kurtis : [00:26:06] Okay, so that theory comes from the fact that leucine is the trigger to stimulate muscle growth, paired with the idea that the body is always in a state of homeostasis, an active balance. Much like a grandfather clock swinging back and forth, as something goes in one direction, it’s going to go in another. You cannot just have a body at baseline, stimulate a process in one direction, then expect it to go back to baseline without dipping into the opposite direction for a little bit.

It’s very much like a sine curve rather than just a straight line. And so if you stimulate muscle protein synthesis but you do not give the actual amino acids to build the muscle with, you will have no net gain. But then after the stimulation, muscle protein synthesis goes away, you will be left with a refractory decline in synthesis rates.

And you don’t need to provide amino acids for that because you have your muscles. They can just degrade on their own. I said decline in muscle protein synthesis, but the theory is it might also stimulate metabolism. So it’s like the sine curve where the stuff you want, you’re not optimizing. But the stuff you don’t want will happen regardless. And so the theory is, if you keep on pulsing BCAAs throughout the day, could you have a net loss of protein if you don’t optimize the positive spikes by actually just having whole foods?

And at this moment in time, there’s no evidence at all assessing this in otherwise healthy demographics, but the theory has been going around a lot with sarcopenia researchers, those who are tending to the elderly and don’t want them to lose any muscle mass. And I can’t really read their research all that well.

But it seems like that’s a valid hypothesis that they’re still testing out. As for athletes, if you wanted a reason to not pulse BCAAs each and every day, then have that be your reason, but I don’t think you’re just going to, like, shrivel up into a little weightlifting raisin if you continue using BCAAs. I doubt it will actually cause any significant muscle loss.

Mike : [00:28:21] Or even any significant impairment of muscle growth. I would assume if you have the basics in place, if your energy balance is where it should be in your macronutrient balance is where it should be and you’re training intensely and whatever.

Mike : [00:28:37] Yeah, because out of all the receptors to be highly sensitized in the body after removing a stressor, the process of building muscle is not usually one of those. Because the molecular target from leucine is actually inside the cell, it’s not a receptor on the outside. It doesn’t need to desensitize and resensitize itself as much as other receptors like the insulin receptor.

Mike : [00:29:00] Interesting. Anything else that’s floating around out there? I’m trying to think. I mean, those cover all the major points of BCAAs, what they are, why people are using them, and why they are vastly overrated and what a legitimate use it may be. Anything else that you’ve had on your list that you think we should touch on?

Kurtis : [00:29:21] In regards to BCAAs, not really, because they are overall a very simplistic preacher. They’ just kind of stimulate muscle growth, don’t do a good job at it, might decrease fatigue in hot environments, of which the fatigue is cognitive, but we pretty much touched down all the bases. It’s still going to be sold all the time. I think the only other thing we can mention is how BCAAs are obscenely cheap and how if you are going to be buying a product all the time, you’re probably actually overpaying if you’re buying one of those brand names.

Mike : [00:29:56] Yeah, they’re expensive.

Kurtis : [00:29:57] Oh yeah, a good tip I guess I should mention is BCAAs in their unflavored form are highly bitter.

Mike : [00:30:03] Yeah, leucine in particular is disgusting.

Kurtis : [00:30:06] Yeah. So if you want to buy bulk unflavored BCAAs, just because they’re cheap, sour and tart are the ones that counter bitter the best. For a tart you can get bulk malic acid which is the little white stuff on the outside of sour candies. That’s just straight-up malic acid, very sour. Sorry, it’s very tart. And then you can also use a bit of lemon juice. Those two alone may be enough to negate how bad BCAAs taste. It can save you a lot of money if you’re going to be taking BCAAs regardless.

Mike : [00:30:41] That, though, probably eliminates one of the main reasons, again, speaking from customers and other people have reached out to us, why people enjoy them is because tasty water and that doesn’t make for very tasty water.

Kurtis : [00:30:56] You have to add a meal flavor enhancer.

Mike : [00:30:59] Yeah. You have to add something like that in.

Kurtis : [00:31:03] And then you just get to the initial price again, eventually.

Mike : [00:31:05] [Laughing] Yeah. That’s also the point like, “how many bags of things are we talking about?” And then you just get back to, “why don’t you just get rid of BCAAs then, and just have the tasty water? And if you don’t want to buy the flavor enhancers, just have some fruit, throw some fruit that you like in water and just drink that throughout the day.

Kurtis : [00:31:28] Yeah, pretty much.

Mike : [00:31:29] All right. Well, this was straightforward. I don’t think there’s anything else that is worth mentioning on the BCAA front.

Kurtis : [00:31:38] Yeah, they’re not really that exciting.

Mike : [00:31:40] Yeah. They just make money. That’s really what it comes down to. There’s so much marketing momentum that has built up around them that, you know, it’s one of those things where the key to lying well is repetition, right? Ideally the bigger the lie, the better. But if you just repeat something, a little factoid, and you repeat it enough until eventually it just becomes accepted and true.

And I feel like BCAAs have reached that point where the lies have been repeated enough times by enough supplement companies in enough media that “everyone knows” now that if you’re into muscles, then you probably should be or you should at least consider BCAAs.

Kurtis : [00:32:27] Yeah, it’s just I really don’t know how to follow up on the old marketing stuff, because it gets me really pessimistic at times. Like at least market the fun stuff, like garlic. That’s cool.

Mike : [00:32:41] Yeah, but garlic is unsexy. It’s smelly.

Kurtis : [00:32:45] I know, but like it has the power of egg farts in your blood to reduce blood pressure. The power of egg farts for health benefits.

Mike : [00:32:55] There is a headline. There’s an ad headline right there. You’ll get readers. I don’t know how many buyers you’ll get, but you’ll get readers for sure.

Kurtis : [00:33:01] Yeah.

Mike : [00:33:04] Well, I think that’s it for this round, as always. Thank you. Thank you.

Kurtis : [00:33:10] Glad to be here.