Branched Chain Amino Acids (BCAA) is one of the most popular supplements the supplement industry wants to sell us. BCAA is each lifter’s dream supplement because it supposedly:
● helps to gain muscle
● prevents muscle breakdown when fasting
● contains significantly fewer calories than protein-rich food or even protein powder
No wonder that almost every serious gym-goer is tempted to supplement with them. Lean Gains, Bro!
But what actually is BCAA?
BCAA is a mixture of three essential amino acids - leucine, isoleucine and valine - that cannot be produced in the human body, however, have very important biological functions.
Leucine, for instance, is crucial for muscle hypertrophy (aka muscle growth) not only because it is an important building block for muscle, but also because it signals the body to start muscle protein synthesis (aka build muscle).
Can BCAA help prevent muscle breakdown when dieting or fasting?
However, a bit of protein powder in water or maybe even some table sugar might do the job as well, whilst being significantly cheaper and having the same caloric content.
If your body doesn’t have enough energy in the present moment and you give your body something that it can burn, it will use it, no matter if that thing is a portion of BCAAs or not.
Great point! Speaking of calories...considering that in both studies referenced above (one examining tracking and the other prolonged skiing), the subjects in the placebo group lost more weight than in the BCAA group and food intake was not controlled for, it’s a no-brainer to suspect that the placebo group lost more weight, thus had difficulties preserving muscle mass, because they were in a higher energy deficit compared to the BCAA supplementation group. It’s not about BCAA, it’s about not eating enough.
Another interesting note; Catabolic state, when the body uses muscle as a fuel in the fasted state, can’t eve nbe reversed by BCAA injection (5).
But what about muscle gains? Can BCAA help us to get bigger?
Indeed, there was an incredibly good sounding research study suggesting that (6). Resistance-trained subjects could gain entire 4 kg lean body mass after an 8-week training program, during which they supplemented with BCAA. Those weren’t newbs! Rather they were experienced lifters. Wow!
The whey protein supplementation group could only gain 2 kg and the carbohydrate supplementation group only 1 kg.
BCAA for the win!
But not too fast. Everything that sounds too good to be true should be particularly questioned.
This study was only presented in the form of a poster at a conference. It wasn’t published in a peer-reviewed research journal. We don’t even have the full research study protocol to know
● What diet participants followed
● If nutrient timing was taken into account
● If the intake of anabolic steroids may have played a role (if researchers excluded lifters on steroids)
Another interesting point is that according to the abstract, the compliance among participants was 100%. Having run research studies myself and knowing how difficult it is to make people stick to a diet, irrespective of whether these are subjects in a research study or clients, it appears very unlikely to me that 36 people could follow the prescribed diet and training protocol to a T for the entire 8 weeks.
Lastly, as I already mentioned, this study wasn’t published in a peer-reviewed research journal. Peer-review means that other researchers check the study carefully before publication and if there are some minor errors, they make the author correct them. Should there be major errors in the research study protocol, they then don’t allow the study to be published.
The fact that this study wasn’t published in a peer-reviewed research journal appears very suspicious to me. I see it as a waste of time and money to run a research study without publishing the results in a journal and simply presenting it just at a conference. Basically, you can present whatever you want as a conference poster because nobody checks it. If you wanted, you could even invent a research study that never took place. Nobody would probably notice it.
Another important point: In order to build muscle, one needs to have all building blocks, all 20 amino acids. BCAA provides only 3 of the building blocks. BCAAs don't increase muscle protein synthesis when taken fasted, as the other building block are missing.
But why not just eat enough protein in the first palace? Why mess around with a BCAA-little-protein-mixture?
Interestingly, the opposite happens when one adds more BCAAs to protein: muscle protein synthesis goes down!
The muscle growth stimulating effect of leucine, the amino acids that sets the signal for muscle growth and is one of the 3 amino acids in the BCAA mixture, may be diminished by the other 2 amino acids in the BCAA mixture, as they probably compete for the same transporters to be absorbed. Thus, BCAA may actually reduce the signal for muscle growth (5, 7).
BCAA seems to be a waste of money that may even reduce muscle growth if you are too enthusiastic about supplementing with it and take too much.
Ohh...did I ruin your mood? Maybe it wasn’t even me, but the effect of BCAA supplementation…
BCAA compete not only among themselves, but also with other amino acids for absorption. This applies also to the amino acid tryptophan, that is the building block for happiness hormone serotonin. The competition between BCAA and tryptophan happens for brain uptake.
Protein-rich meals, for example, were shown to decrease happiness, as tryptophan is outcompeted by other amino acids (especially essential amino acids), which results in a poor tryptophan brain uptake from the bloodstream. For this reason, foods high in tryptophan and low in protein may have the highest mood boosting effect.
In contrast, carbohydrate-rich meals have been shown to enhance the mood, as they indirectly boost tryptophan uptake into the brain (8). Mechanism of action seems to be that carb-rich meals lead to an increase in insulin level. Insulin makes our cells (e.g. muscle) take up various amino acids, especially BCAA, leaving more tryptophan in the blood stream. This increases ‘tryptophan to total amino acid’ ratio in our blood stream and results in a higher tryptophan uptake by our brains. More tryptophan in our brains results in a higher serotonin production and our mood increases.
Personally, I don’t think that BCAA supplementation should lead to major problems with the mood. However, if someone is susceptible to it and is in a ‘my-life-sucks-depression-phase’, maybe reduction in BCAA intake could be a thing to experiment with.
Anecdotally, I had a few clients who were on antidepressants and noticed some unexpected side effects after increasing their protein intake, thus also BCAA intake. So, if you are in similar situation and notice something weird happening with your brain, it may be a good idea to decrease your BCAA intake to see if you get better.
My last advice: Don’t try to find any magic supplement that will give you more gains or try to trick nature. It doesn’t work. Just eat your food and lift!