Should You Take Branched Chain Amino Acids?

Lately there has been so much buzz around branched chain amino acids (BCAAs). You may have heard of them being taken in supplement form; or maybe you’ve never heard of them until now. So what are BCAAs exactly? We’ve all heard of essential amino acids – the 20 amino acids that the body can’t synthesize, and therefore must be ingested through diet. Amino acids in general are known for being the “building blocks” of protein in the body. So without them, many biological processes cannot occur. 3 of these essential amino acids are considered “branched” because they have a branched chemical structure. These 3 are called isoleucine, leucine, and valine (pictured below). So what’s all the buzz about these new supplements? What do people believe they can do for them? And are these believed effects backed by research?


Listed below are some of the main claimed effects of BCAA supplements:

  • Decrease muscle soreness
  • Build lean body mass
  • Provide steady energy
  • Increase fat loss
  • Lessen mental fatigue
  • Enhance physical/athletic performance

Research Findings

The above claims can be found on any BCAA manufacturer’s website. But what does the research show about these supplements? Do they really provide all of the claimed effects for its user? Here are a few things that research has told us so far.

Decreasing Muscle Soreness // Building Lean Body Mass

Some studies have shown that taking BCAAs prior to a workout can lead to reduced muscle soreness post-workout. How is this done exactly? When we exercise, BCAAs are broken down to provide energy. (BCAAs break down in the muscle, whereas most other AAs break down in the liver.) This being said, it has been shown that supplementing BCAAs prior to exercise can help spare this breakdown of BCAAs in the muscle, therefore reducing overall post-workout muscle soreness.

It has also been shown that taking BCAAs can increase rates of protein synthesis and decrease rates of protein degradation during a rested state. Likewise, when recovering from endurance exercise, BCAA supplementation has been shown to increase muscle building, due to changes in certain signaling pathways. All of this being said, BCAAs appear to play a role in building lean body mass.

Providing Steady Energy

When someone uses the term “steady energy,” they are generally referring to something that prevents dramatic changes in blood sugar levels. So are BCAAs considered a good source of steady energy? Well, yes and no. First, BCAAs may help regulate blood sugar levels by helping to preserve the sugar levels of the liver and muscles (where sugar is generally stored) during exercise. The BCAA isoleucine may also increase uptake of sugar from the blood into the cells.

While all of that is true, there have also been studies that are more concerning. Several studies have found a correlation between increased BCAAs in the blood and insulin resistance (aka diabetes). While the exact reasoning or mechanisms behind this aren’t entirely known yet, it’s important to keep in mind, especially if you have diabetes or are at risk for diabetes.

Increasing Fat Loss

While it has been shown that exercising individuals who consumed BCAA supplements can lose more fat mass than those who have not, it is also important to note that this could be due to the fact that they are simply getting increased protein, the BCAAs are replacing something that would be more sugary (like a sports drink), or the effects on muscle soreness/lean body mass discussed above are occurring. Therefore, I would not necessarily recommend BCAAs to someone simply because they want to lose fat mass. However, it may be one of the effects.

Lessening Mental Fatigue

BCAAs have been shown to reduce the production of serotonin in the brain, reducing mental fatigue and increasing mental agility during and after exercise. It has also been shown that BCAA supplementation can increase resistance to fatigue during long bouts of exercise.

Enhancing Physical/Athletic Performance

For many of the reasons listed above, BCAA supplementation may enhance athletic performance. Decreasing muscle soreness, increasing lean body mass, and lessening fatigue could all likely contribute to improved performance. These supplements have, in some cases, increased individuals’ ability to exercise for an extended period of time. However, other studies have shown that BCAA supplementation does not impact physical performance.

Certain Medical Conditions

When I personally think of BCAAs, I tend to think of 2 specific medical conditions: hepatic encephalopathy and maple syrup urine disease.

Hepatic encephalopathy is characterized by a buildup of toxins (primarily ammonia) in the brain, usually caused by liver dysfunction. When the liver’s normal detoxification processes are hindered, another way the body can filter out ammonia is through the amidation process of glutamine synthesis in the muscles using BCAAs. Therefore, BCAA supplements are sometimes used as a treatment mechanism for hepatic encephalopathy, which has been shown to be beneficial.

Maple syrup urine disease (MSUD) is a rare condition that requires the opposite approach. As a genetic disorder resulting in the body’s inability to process BCAAs properly, MSUD can result in a dangerous buildup of BCAAs in the blood. Therefore, this condition requires restricted dietary BCAAs. This is a specific instance in which BCAA supplementation would not just be unbeneficial, but harmful.

It has been shown that increased BCAAs in the blood (from dietary sources or otherwise) may have negative effects in the long-term, potentially increasing risk for obesity and shortened lifespan. In general, moderation is always a good idea. Be sure to get all of the essential amino acids and not just the BCAAs. This balance will prove to be beneficial later in life. An easy way to go about this is to get your amino acids from food sources rather than supplements. Good sources of BCAAs (and the other amino acids) include animal protein (meat, poultry, fish, milk, eggs), nuts, seeds, legumes, and soy products.

My General Recommendations

You may have just skimmed past most of what I just said, in which case – let me summarize for you. In short:

  • BCAA supplementation prior to exercise may be beneficial for increasing/maintaining muscle mass and/or reducing post-exercise soreness.
  • BCAAs may be a good source of steady energy; however, it’s important to use caution if you have diabetes or any other conditions with abnormal blood sugar. The exact effects on blood sugar are not yet entirely understood.
  • BCAA supplementation may help to lessen mental fatigue both during and after exercise.
  • There are mixed results as to whether or not BCAAs help improve physical performance. In general, I wouldn’t recommend supplementation as your primary method of improvement; however, it may contribute in some way.
  • As a general rule, it’s always a good idea to talk to your doctor and/or dietitian prior to starting any new supplement. This is especially true if you have certain medical conditions that could interact negatively with specific supplements.
  • Moderation is key. Don’t overdo it on BCAAs. Be sure to get all of the essential amino acids in your diet. In general, I recommend first looking to food sources (listed above) rather than supplementing. Only after you have determined that your dietary sources of BCAAs are inadequate with a medical professional would I recommend resorting to supplementation.

I hope this post was instrumental in helping you decide whether or not BCAA supplements are right for you! Please feel free to reach out if you have any questions!

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