The Truth about BCAAs

Filed under: Nutrition

One of the most popular supplement choices around today are branched chain amino acids (BCAAs). These BCAAs are three essential amino acids found in high concentrations in things like whey protein, casein protein and meats. People use them for muscle building and during fat loss phases, and there is some research backing up their validity. But do they work as some people claim, or they are are they just another overpriced moderately useful supplement to complement a balanced diet?

The most popular ways of taking BCAA’s are either during training, or between meals. Are either of these applications beneficial? First let’s look at taking BCAA’s around training for muscular growth.

A good practice for most people would be to have protein surrounding your training, to enhance recovery and prevent protein breakdown. If adequate protein is consumed, for example 20g of whey protein before training and 20g of whey post training (for simple numbers), you get ample amounts of BCAA’s (~10g). If adequate protein is consumed throughout the rest of the day, are a few extra grams of BCAA’s really going to make a significant impact upon your gain in muscular size? Unfortunately, the research is not very clear on this. Most research done on BCAA’s does not use an adequate amount of protein intake around training or throughout the day. While it may show that BCAA’s are beneficial, this lack of adequate protein is a HUGE flaw in the research. Without adequate protein intake the BCAA’s make up for that lack of protein, and therefore they appear very beneficial, promoting increases in muscle gain over just the control. With adequate protein intake (and therefore a sizeable BCAA intake) I have my doubts that the impact will be anything above negligible.

Now let’s look at taking BCAA’s while dieting, though granted there is not a lot of research on this topic either.

Though there isn’t a lot of hard data, there is a lot of anecdotal evidence that consuming BCAA’s while dieting can improve fat loss and help maintain lean mass. When dieting, adequate protein intake is even more important than when trying to gain mass. When in caloric excess, carbohydrates are protein sparing and they can help prevent the oxidation of protein as an energy source. When in a caloric deficit, which is often times achieved by decreasing carbohydrates, protein is now less protected. So increasing protein intake or ensuring adequate protein intake while dieting is incredibly importance to retain lean mass. This will help to make sure that lean mass is preserved by having dietary amino acids oxidized, not body amino acids, and branched chain amino acids are the best dietary sources of amino acids to be oxidize for fuel. In other words, they are more easily oxidized than other amino acids, and therefore preferred by the body. This can be very important when dieting especially around training. When dieting BCAA’s are a low calorie energy substrate that also enhance muscle protein synthesis, seeming like a win win situation. So are BCAA’s magic when dieting as your peri-training nutrition? Maybe, maybe not, but they at least provide some benefits while providing significantly less calories than a protein and carbohydrate shake.

When dieting BCAA’s are also often consumed between meals to also preserve that lean mass. Though again little to no hard data exists on the topic, there is a mountain of anecdotal evidence that for some unexplained reason sipping BCAA’s between meals not only helps preserve lean mass, it can help promote fat loss. The theories abound, but no one is really sure why, or if it is still possibly a placebo effect. Maybe these people are just training harder or sticking to their diet better because they feel less hungry and more energized? Who knows. Regardless of why, it does seem to work and it may not be a terrible idea.

In conclusion, I think BCAA’s are a moderately beneficial supplement that have applications at certain times and/or phases of the year. If you are dieting hard, or in an extreme caloric deficit BCAA’s can be very handy to preserve that lean mass and potentially increase fat loss. For someone trying to gain mass I think BCAA’s are just an expensive addition to someone in a caloric excess and they have a negligible impact on increased muscle protein synthesis, compared to just ensuring adequate protein intake since that will be high in BCAA’s already. Spend that money on actual food and just watch yourself grow.

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Posted on August 25th, 2009 by Brian St. Pierre


  1. Arthur Says:


    Even during fat loss phases, would it be just as sensible to stick with usual pre/post nutrition or a slightly modified version of rather than going with added BCAA’s?

    Some folks seem to feel that para-training nutrition should be the last thing to be manipulated as it is, and that the protective/performance benefits outweigh whatever minimal hit there may be to fat /oxidation loss.

    And I’ve seen it been said that 5 grams of leucine is comparable to much higher doses of BCAA’s, so would spiking whatever pre-training nutrition is used with 3-5 g leucine be an even better way to go, or would this, too, possibly be extraneous?

    It feels like you could get tied in knots on such topics as the days of finding something that work and sticking to it seem to have been replaced by constant refinement and “about faces” due to the sheer quantity of info (some golden and some utter crap…..although hard to distinguish sometimes) out there and the ease with which people can access it.

    As always, thanks for the time and the knowledge.

  2. Brian St. Pierre Says:


    As usual a good question. I would say…it depends. It depends on results, more than anything else. I am a results oriented guy, and if what people are doing is working, why mess with it?

    For some people if psychologically speaking they can’t alter their para-training nutrition, then we can manipulate in other areas. Leucine is the big key, and I don’t see an issue with adding it, but don’t expect these massive results. It might not be helping any more than your adequate protein intake already is.

    You can definitely over think it. To me things are very simple. Eat real food. Train hard. Recover well. Repeat.

  3. Optimium Pro Complex Facts & Reviews Says:

    [...] The Truth about BCAA’s                                                                                                               One of the most popular supplement choices around today are branched chain amino acids (BCAAs). These BCAAs are three essential amino acids found in high concentrations in things like whey protein, casein protein and meats. People use them for muscle building and during fat loss phases, and there is some research backing up their validity.  Mail this post [...]

  4. Florence Muhs Says:

    Good site. I continually train hard at least three times a week and after a challenging session your body wants the best quality protein to repair you for your subsequently workout. I always go for lean protein as the best muscle building food, mostly chicken, turkey as well as fish. I as well consume scrambled egg whites for breakfast.I normally combine these meals with a complex carbohydrate as well as veg as well. I keep away from protein shakes as I see them as a waste of money, the body is intended to digest foods and drinks lack the thermic affect of food.

  5. Sherrie Grany Says:

    Hi, even though I agree with most of what was stated outlined in this article you will find some I just do not go along with whatsoever. Even with that stated, this was an overall good quality post.

  6. Shoshana Medine Says:

    I usually enjoy your posts but sorry to say but this time you might have been too tired when writing because the article it seems rushed.

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