BCAAs for Bodybuilders: Just the Science (Part 1)


Though BCAA supplementation is used by several populations with contrasting goals (e.g. bodybuilders and other aesthetic pursuits, strength athletes, the elderly or other individuals with the potential for lean body mass losses), this article will focus purely on the bodybuilder with the objectives of gaining more muscle mass, maintaining muscle mass, or maintaining muscle whilst losing fat.


What are BCAAs?

Branched-chain amino acids (BCAA) are named after their branching chemical structure and consist of the three essential amino acids: leucine, isoleucine and valine. BCAAs are one of the most popular supplements available on the market. Their popularity may rest in some part to the unique role of BCAAs, in particular, leucine, regarding the modulation of protein synthesis via the stimulation of the biochemical sensor, the mammalian target of rapamycin (mTOR). In addition to their commercial use, BCAAs have been extensively studied in a number of roles relevant to athletic performance, including: immune function, central fatigue, sparing lean body mass, attenuating markers muscle damage and promoting muscle protein synthesis (MPS). Unknown to a lot of trainees, probably due to clever marketing, is the fact that BCAAs are found in whole proteins and are often cheaper on a gram per gram basis compared to their isolated counterparts. In addition to their BCAA content, whole foods contain all the additional amino acids and offer other benefits (some potentially anabolic) that go along with them (e.g. generally better satiety, various vitamins & minerals, and therapeutic properties) (Table 1).


Table 1: BCAA and leucine content of foods

Source for data.    *Products from www.myprotein.com


From table 1, you can see that high quality proteins such as animal flesh, eggs and supplements derived from milk, contain quite a high percentage of BCAAs. On a gram per gram basis, you get more than double the amount of BCAAs for your money if you opt for a high quality whey protein isolate than if you were to purchase isolated BCAAs. As such, why would someone not just opt for a whey protein supplement if they were looking to bump up the content of protein or BCAA in their diet? After all, it would offer the same convenience (probably more so if you account for the awful taste of BCAA powders).

Is there a benefit to BCAAs?

As stated earlier, there has been a fair bit of research examining the effects of BCAA supplementation on various aspects relating to performance and body composition. Indeed, several studies have in fact shown BCAA supplementation to positively impact body composition (i.e. improve muscle gain or fat loss), support immune function and reduce markers of muscle damage. All seems good so far? Not quite. With a closer inspection of the data, these outcomes are unsurprising, as it is clear that protein is always insufficient in the first place. So essentially, what these studies are showing is that adding BCAAs to a diet containing inadequate protein (by my standards, at least), their addition may improve the dependent variable/s that the researchers are looking at.

For example, in a study often-quoted by the companies/people looking to sell BCAA supplements, Mourier et al. (1997) examined the effects of 52 g of BCAAs on body composition during three weeks of caloric restriction in a group of competitive wrestlers. In this study, the wrestlers were given a diet consisting of 28 kcal/kg/day with 20% protein. This equated to roughly 80 g of protein per day (or 1.2g/kg) for a 68 kg wrestler. It was found that the supplement group, who ingested an additional 52g of BCAAs, spared more LBM and experienced slightly greater fat losses compared to the control.

In a study published in an Italian journal, the authors compared the effects of 0.2 g/kg of BCAAs with a non-caloric placebo taken 30 minutes before and after training, on bodybuilding progress in a group of experienced drug free bodybuilders (with at least 2 years training experience). The BCAA group showed better gains in body weight, arm and leg circumference, and squat and bench press performance. So essentially, using a 90 kg athlete as an example, this study showed that adding 36 g of BCAA around a workout is better than ingesting nothing. A 'bro' could’ve told you that!

These studies are often cited as ‘proof’ that you need massive doses of BCAAs, particularly around training. I think otherwise. Firstly, the subjects in the initial study consumed insufficient protein (1.2g/kg per day). In my previous article on protein requirements, I came to the conclusion that 2.5-3 g/kg would be more appropriate for strength/power athletes. Using a 68 kg individual as an example, this would mean a protein intake of 80 g vs. 170-204 g per day, a difference of about 18-25 g of BCAA per day from whole food sources (more so, if whey were to make up a significant proportion of the added protein intake). Though it is unknown whether the wrestlers would’ve still outperformed the control group given a sufficient protein intake in the first place, I have my doubts.

Speaking of protein insufficiency, it is no surprise that a mega dose of BCAAs around training was superior to consuming nothing around training. This study by Cribb & Hayes (2006) perfectly demonstrates the importance of the provision of nutrients around training. Given a sufficient protein intake in the first place, as well as the provision of whole foods around the training bouts, it is also unknown whether the BCAA group would have outperformed the placebo control.  Specifically, since I recommend consuming 40 g of protein within a two-hour window prior to and after training (80 g total), 80 g of protein would provide roughly 15-20g of BCAAs (depending on the source) around the training bout as well as all the other amino acids. For these reasons, I also have my doubts that additional BCAA supplementation on top of my whole protein recommendations, would prove any additional benefit.

Though there is research demonstrating the benefits of BCAA supplementation regarding the promotion of muscle protein synthesis and preventing muscle protein breakdown (MPB), whether this holds true in the presence of sufficient amino acids from whole food sources remains to be properly studied. As such, given that whole protein sources such as whey are more economical than isolated BCAAs, and that the vast majority of people looking to build muscle are already consuming (with many possibly exceeding) a protein intake that I consider adequate(2.5-3 grams per kilogram of body weight), the real question we should be asking is, whether adding BCAAs to an already high protein intake will offer any benefit. Or, an additional question is whether there is something unique about isolated BCAAs. Specifically, will isolated BCAAs offer something that adding more protein from whole foods will not (i.e. does their structure or their caloric economy offer any benefits to body composition)? In the following section and in a future post, I’ll attempt to answer these vital questions.


Is a high protein intake sufficient at optimising muscle gain?

To my knowledge, no published studies have examined the effects of chronic BCAA supplementation on body composition alongside a structured resistance-training program, and in addition to an already high protein intake. Luckily, there is a study that fits these criteria, and is the only one that comes close to answering the question of whether adding BCAA to a pre-existing sufficiency of protein yields any benefit. It isn’t fully published, but is available on the ISSN website in the form of a poster presentation. Stoppani et al. (2009) examined the effects of a supplement (Xtend) containing BCAAs on body composition and strength following an eight-week resistance-training program in 36 strength-trained males with a minimum of two years weight training experience. The participants were assigned to one of three groups and were to receive one of the following, during their eight week program: 14 g BCAAs (BCAA), 28 g whey protein (WHEY) or 28 g of carbohydrate from a sports drink (CHO). The BCAA group gained 4 kg of lean mass whilst the WHEY group gained 2 kg of LBM over the course of eight weeks. For completeness, the CHO group gained 1 kg of LBM in eight weeks. In addition, the BCAA group lost 2% body fat in the eight weeks whilst the WHEY and CHO groups both lost 1% body fat. To top things off, the BCAA group gained a greater amount of 10-RM strength in the bench press (6 vs. 3 kg) and squat (11 vs. 5 kg) compared with the WHEY group.

Interestingly, these results occurred despite a habitual daily protein intake of 2.2-2.4 g/kg. At closer inspection, these results do appear to be too good to be true. Indeed, a gain of 4kg of LBM in just eight weeks, with a concomitant decrease in body fat of 2%, seems a little farfetched, especially when you consider that these subjects were drug-free, experienced weight trainees. In my articles of maximum muscular potentials, I mentioned that a novice could expect to gain about 1kg per month (assuming they get everything right training and nutrition-wise). Achieving double this amount of muscle gain in experienced trainees just doesn’t seem right. When results appear this good, I look to see who funded the study. It was in fact Scivation, the makers of the Xtend product that was tested, who funded the study. While funding does not automatically invalidate study findings (they have to get the funding from somewhere!), it may bias the results somewhat. My thoughts on the matter echo those of Alan Aragon who discussed this trial in the February 2010 issue of his monthly research review:

“The skeptic in me is tempted to chalk up some of the results to not just funding source (Scivation), but also the longstanding friendship [my link] between Jim Stoppani and the Scivation staff. The fact is, there’s no way to quantify the degree of commercial bias inherent in this trial – or any other for that matter.”

With all things considered in this trial, I find it highly unlikely that the provision of an extra 7 g of BCAA per day in the BCAA group would have outperformed the WHEY group to such an extent. As such, I would like to see similar trials conducted before recommending the addition of BCAA on top of an already sufficient protein intake.


Conclusion (for now)

To summarise so far, we have learned what BCAAs are, their unique role in protein synthesis, as well as what foods they are contained in and in what percentages (table 1). At first glance, the extravagant marketing claims and suggested protocols of usage seem to be backed by scientific research. However, as we dig a little deeper, it seems unlikely that these benefits would exist in the presence of a sufficient protein intake. Though additional BCAAs might be beneficial to bodybuilding goals (i.e. more muscle and less fat), the research has yet to show these effects. If such effects do exist, they are likely to be miniscule. Because of this, they would only be something worth considering for the elite physique athletes who are looking for that extra 1-2% to gain an advantage over their competitors. For the majority of people just looking to improve their body composition, I see them as an unnecessary expense; focusing more on what delivers (i.e. progressive strength gains in the main compound lifts in addition to a well-structured nutrition protocol) will allow them to reach their desired goals (and more). In the absence of sufficient scientific evidence, from my experiences both personally, as well as client feedback, adding BCAAs to a diet of adequate protein consumed appropriately around training, has failed to produce any noticeable benefits, despite the potential for placebo effects.

To give this topic appropriate justice, I will be splitting it into two or more parts. In subsequent posts, I will examine the research behind between-meal dosing of BCAAs (popularised by Dr. Layne Norton) and the rationale for their use whilst dieting. I will end the topic of BCAA supplementation by tying things up with an overall summary and offer my practical recommendations.

Click here for part 2.

If you enjoy my writings, please follow me on twitter (@JosephAgu) and don’t forget to subscribe to the blog to be informed of future posts -->