Last updated on September 25th, 2018

BCAA – branched chain amino acids that consist of three amino acids: Valine, Leucine and Isoleucine. As all the rest amino acids, BCAA complex is the basic component building up the muscle tissue. Moreover, BCAA provide anabolism and anti-catabolic effect. Because BCAA are not synthesized in the human body, athletes can only get them with foods or sports supplements.

BCAA are metabolized in muscles, increasing bodybuilders’ athletic performance, improving their health and providing energy.

BCAA mechanism of action

Energy supply

When bodybuilder performs physical exercises, the oxidation of BCAA increases, being transformed into glucose and glucose into energy. After each intense workout, the levels of BCAA are much lower than at rest. It means that BCAA storages are wasted on metabolism and breakdown of muscle proteins. Therefore, if sportsmen use BCAA sports supplements, they replenish the BCAA pool, preventing the muscle breakdown.

Some scientists believe Leucine is the main energy source in the human body. Leucine oxidation in the body gives even more energy than glucose does. Given this, both glucose and BCAA are powerful sources of energy and act independently. As a result of these two different oxidation processes, an athlete gets twice more energy within a short time.

BCAA fat burn

Metabolism, body weight, fat storage and weight loss are regulated by one hormone, called leptin. Leptin secretion depends on the amount of fat tissue in the body: the more fat tissue the higher the leptin secretion. When the amount of leptin is low (because of fat loss), the appetite increases and the metabolism is slow in order to save energy stores (fat tissue). Therefore, when men reduce the caloric value of their diet, their body weight sometimes stays unchanged.

To increase the secretion of leptin and launch the weight loss process, men should use BCAA. In this case, BCAA provide a rapid supply of proteins. The body does not store fat anymore; since it “thinks”, it gets food. BCAA suppress the appetite and increase the energy supply by burning fat tissue.

Muscle protein synthesis

As the main component of muscle proteins, BCAAs help building a muscle mass. But this refers to free amino acids only. If there are no free amino acids in the body, muscles stop growing. If you need to refill your amino acids consumption, all you need is to take some protein (food or sports nutrition). It is known that protein is absorbed in the intestines gradually. Please note that after workouts your body needs much more amino acids than before physical loads. Thus, BCAA sports supplement replenishes the amino acids pool and builds up new muscle fibers.

BCAA can transform into Glutamine. Glutamine is a substance, regulating the protein synthesis, increasing anabolism and the release of human growth hormone.

Mammalian target of rapamycin, or simply mTOR is a protein, regulating the cell growth and the synthesis of new protein. As you know, the synthesis of protein is the process requiring much energy. It has been proven that Leucine activates mTOR. Thus, branched chain amino acids provide the necessary amount of building material and energy.

BCAA in bodybuilding

As mentioned above, BCAA can protect muscles from breakdown, reducing the fat tissue, increasing strength and building lean muscles. In addition, BCAA supplement increases the efficiency of other sports supplements.

The effectiveness of BCAA was proven during clinical trials. Some of the trials are given below:

Elisabet Børsheim – Essential amino acids and muscle protein recovery from resistance exercise

The trial conclusion.
From this clinical trial, it is getting clear that essential amino acids speed up the synthesis of muscle protein. According to the experiment, the higher the dose of BCAA, the higher the anabolic effect.

Yoshiharu Shimomura – Exercise Promotes BCAA Catabolism: Effects of BCAA Supplementation on Skeletal Muscle during Exercise

The conclusion.
Obviously, fatty acids are among the agents that can regulate BCAA metabolism. Moreover, the trial has shown that during physical exercises, an athlete’s body needs a great amount of BCAA, so if athletes take BCAA soon after (or before) the workout, their muscles are protected from breakdown.

Jim Stoppani – Consuming a supplement containing branched-chain amino acids during a resistance-training program increases lean mass, muscle strength and fat loss

The conclusion.
When athletes were using BCAA within 8 weeks of high-intensity training, the amount of fat tissue in their bodies had noticeably reduced, building up the lean muscles and increasing the strength rate during squats and bench press exercises.

Mero A. – Leucine Supplementation and Intensive Training

The conclusion.
When sportsmen added BCAA (Leucine) to their daily diet, they managed to increase the lean muscles, their strength rates and reduce muscle proteolysis. As a result, they managed to reduce the amount of fat tissue in their bodies.

When do I need to take BCAA?

If you want to lose weight, you need to take BCAA before each workout and soon after it. You can also take soluble (liquid) BCAA during your training. To suppress the appetite and catabolism, it is better to use BCAA between main meals. In addition, you may use some protein supplements to achieve these goals, if BCAA are too pricey for you.

If you gain muscle mass.
The best time of use is before, during and after the workout. Athletes recommend to make an energy drink: BCAA serving and a little sugar all mixed with water. This shake is best to use during the workout to supply your body with water, amino acids and carbs throughout the workout. Please note that your body needs BCAA during and after training only. During this period of time, BCAA provide the most powerful effect to the body. So, it is better to use these amino acids before and after the workout. If you use a liquid form, you can drink it during your workout as well. In addition, some athletes take a serving of BCAA after awakening, to prevent morning catabolism.

BCAA dosage

BCAA dosage ranges between 4g and 8 g for both muscle gain and weight loss. Make sure you take it 1 to 3 times a day. If you are training hard, then the lower doses will not meet all your body’s needs.

It is a fact that some BCAA supplements are quite pricey. Moreover, some manufacturers produce BCAA in small doses, so you should check the label before buying BCAA supplement. BCAA sports supplement is completely safe, so you can keep using it as long as you need. Please note that protein supplements also contain some BCAA. So when you calculate your daily serving of BCAA, please consider this.

BCAA is perfectly combined with any sports nutrition kind. If you want to gain muscle mass, you should better combine BCAA with proteins, gainers, anabolic supplements and creatine.


  1. Nishitani et al. 2002 и Layman, 2002
  2. Freund and Hanani (2002)
  3. Exercise Promotes BCAA Catabolism: Effects of BCAA Supplementation on Skeletal Muscle during Exercise”. J. Nutr. 134 (6): 1583S-1587S. 2004. Retrieved 22 March 2011
  4. Dennis et al., 2001
  5. Layman, 2003
  6. Shirmomura et al., 2004.



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