BCAAs and their effects on the body


What are BCAAs? 

There are 20 amino acids in the body which create thousands of different protein chains. Nine of them belong to essential amino acids, which means that the body is not able to create them on its own and they need to be received by the means of food or supplements. Three of these nine amino acids are denoted as BCAAs[3]

The acronym BCAA comes from the English name Branched Chain Amino Acids, therefore amino acids with branched chain. By the term BCAAs, we denote specifically three essential amino acids, and these are leucine, isoleucine and valine. They differ from the rest of the amino acids by metabolising directly in the muscles than in the liver. [1]

They also differ in the effects [33]:

  • leucine increases protein synthesis, helps to build and regenerate muscles. It supports insulin regeneration and is one of two amino acids which can’t be transformed into sugar.
  • isoleucine regulates glucose consumption and by this, it enables to store energy into the muscles and not into fat cells
  • valine improves brain function, reduces tiredness and serves as prevention against protein break down

BCAAs play important roles in the body, and these are protein synthesis, energy production, formation of other amino acids such as alanine and glutamine, or leptin regulation. [2] Everything about the effects of amino acids with branched chain will be said in the following lines of the article.

What are BCAAs?

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7 effects of BCAAs for the body

BCAAs are known as supplements for sportsmen but they bring not only health benefits to them. Like the essential amino acids, they are needed for the right functioning of chemical processes in the body. The fact that they can help you to get your dream body is only icing on the cake.

1. They increase protein synthesis and muscle growth

Amino acid leucine has the ability to activate and to stimulate protein synthesis in the muscles which is the way to muscle mass growth. This effect makes BCAAs anabolic and anticatabolic weapons. [4] This is proved by several studies.

Synthesis of the muscle proteins happens when the amino acids are united into muscle tissue. Protein synthesis stimulates insulin production which enables the muscle cells to be used as source of energy sugar in blood. The insulin production supports releasing of amino acids for the muscles. [3]             

BCAA -  increase protein synthesis and muscle growth

One research tested the effects of BCAAs on the group of people who were receiving 5,6 g of BCAAs after resistance training. It was shown that they had better protein increase in the muscles in 22% in contrast to those who were consuming placebo. [9]

Another research says that BCAAs in combination with whey protein can increase protein synthesis in more than 50%. [5] [6] Whey protein as the source of all the essential amino acids, reinforces the BCAA effect for building and growth of the muscle mass. For maximizing of the BCAA results, there is a need to supply the rest of the amino acids by form of protein or food.[7] [8]

BCAA -  increase protein synthesis and muscle growth

2. They reduce fatigue

The researches confirmed that BCAAs reduce muscle damage which is the training consequence. They can also help to shorten the period of muscle pain. Some studies showed that BCAA receive had reduced the protein break down during training and had an increased level of the enzyme creatine kinase which is the indicator for muscle damage. [10] [11] [12]

In one study, people who were using BCAA supplement before training of the squats, significantly reduced the muscle pain and fatigue in contrast to the group which was receiving placebo. [13] BCAA supply before training can speed up the period of regeneration of the muscles. [14] [15]

3. They reduce tiredness after exercising

BCAAs can help you not only to reduce soreness but also the tiredness caused by exercising. The exhaustion from the training is dependent upon several factors, including the intensity and time of exercising, also the surrounding and your physical condition. [16]

During training, the muscles use storages of BCAAs which cause their natural decrease in blood. When the level of BCAAs drops, the volume of tryptophan in the brain increases. Tryptophan then changes into serotropin, the brain substance, about which there is assumption that contributes to increased tiredness during training. [17] [18] [19] [20]

Two studies confirmed that people who were supplying BCAAs, had higher concentration during training. This is the direct result of the effects of BCAAs for tiredness reduce. However, this effect doesn’t have the impact on the performance improvement during exercising. [21] [22]

4. They form alanine and glutamine

The human body needs alanine and glutamine in higher amount mostly during training. It is because of the increased protein breakdown in the muscles which can cause the muscle mass loss as long there is non sufficient amount of the amino acids in the body. The supplementation of BCAAs will provide the sufficient amount of material for alanine and glutamine production from other parts of the body than from your bicepses. [34]

Intensive training with weights causes highly catabolic condition. The glycogen storages are rapidly exhausted and the liver has to synthetize the glucose with the help of L-alanine in order to produce the sufficient amount of energy. The BCAA supplements can help you maintain alanine level which is needed for good performance.   

Drinking of BCAA drink can help the body to create amino acid glutamine in skeletal muscle. During this process, glutamine regulates the protein synthesis and nitrogen balance. [35] [36] You will get more about the other effects of glutamine for sportsmen in our article.

5. They regulate leptin level and support fat loss

Receiving of supplements with leucine stimulates the effect of leptin hormone. [37] Leptin influences regulation of metabolism, weight and appetite. The excretion of leptin is associated with the fat level in the body. More of the body fat causes higher leptin secretion, while within the low fat level, the excretion of leptin is small. [2]

When you are in low-calorie diet in order to get rid of the body fat, the amount of leptin which you produce, decreases. Your body wish for food in order to supply low fat storages. Leucine has the ability to activate leptin effect and its function is that the body has the feeling of sufficient calorie receive which maintains the smooth process of diet and metabolism. [2] Thanks to this, you can effectively reduce the body fat and weight.

BCAAs - They prevent from muscle loss

6. They prevent from muscle loss

Proteins in the body are breaking down and synthetising all the time. The balance between these two effects is denoted by the amount of proteins in the muscles. [23] The loss or break down of the muscle happens when the break down of the protein exceeds protein synthesis. The muscle mass loss is the result of malnutrition and it occurs when there are infections, cancer, also in the lenten season and it is a natural part of ageing.


In the human body, there are about 35% of essential amino acids BCAA in the muscle proteins which create 40% of all amino acids needed for the body. [24]

That is why it is important that BCAAs and the rest of the amino acids were in the period of the muscle mass loss recompensed and were able to prevent this loss. Several studies support the use of BCAA supplements for limiting of the muscle protein break. According to researchers, they can improve the health and overall life quality of older and sick people. [25] [26]

7. They reduce the symptoms of liver diseases 

Amino acids BCAAs can improve the cirrhosis, therefore chronic disease of the liver. It is estimated that within 50% of people with cirrhosis, it develops into hepatic encephalopathy, the disease which causes the brain function loss. It comes to it, when the liver is not able to eliminate toxins from blood. [27]

While some antibiotics are the main treatment at hepatic encephalopathy, BCAAs can significantly reduce its process. One analysis of 16 studies with 827 patients confirmed that supplementation of BCAAs had contribution to symptoms of this disease. [28] [29]

The cirrhosis of the liver is the main risk factor for the development of hepatocellular carcinoma which is the most common form of liver cancer. The effects of BCAAs positively act on the process of this disease. [30]         

Several studies showed that using of BCAA supplements can serve as the prevention against liver cancer within people suffering with cirrhosis. The specialists recommend to supply BCAAs for the treatment of liver diseases and prevention of complications. [31] [32]

BCAAs - They reduce the symptoms of liver diseases

The source of BCAAs

BCAAs can be found in food and in protein supplements or as the single supplements. They are available in the form of powder, BCAA energy drink or capsules.

Food with high protein content, mostly meat, whey, fish, eggs and milk products belongs among the natural BCAA sources. You can have a look at the amount of BCAAs included in food in the following table. [3]

Beef meat100 g6,8 g
Chicken breasts100 g5,9 g
Whey protein1 dose5,5 g
Soy protein1 dose5,5 g
Tuna in can100 g5,2 g
Salomon100 g4,9 g
Turkey breasts100 g4,6 g
Eggs2 pieces3,3 g
Parmesan50 g4,5 g
Greek yoghurt140 g2 g

The recommended daily amount of BCAAs

The standard dose of isoleucine is 48 – 72 mg per kilogram of body weight. The recommended dose of leucine is between 2 – 10 grams. This is approximately 20 g of combined BCAA amino acids with balanced proportion of leucine and isoleucine per day. [39]

One dose of BCAA supplement should contain 5 – 10 grams, while it is dependent upon the right timing.

It is ideal to supply BCAAs 30 – 60 minutes before training and immediately after training. It is suitable to mix BCAAs with water and to supply them during training in order to have the sufficient amount of energy and at the same time, to reduce tiredness.[39] [40]

The proportion of amino acids in BCAAs 

If you are choosing between BCAA supplements, different amino acid proportion can confuse you. The most frequently, there is proportion of 2:1:1, therefore two portions of leucine and one isoleucine and valine. Between supplements, there can be found also BCAA in proportion of 4:1:1, 8:1:1 and even 10:1:1. The companies substantiate too high doses of leucine by positive effect on muscle growth. The reality is that the production of 8:1:1 proportion and 10:1:1 proportion is cheaper.

If it is concerned with the proportion of 2:1:1, it is the most typical division of BCAAs which are found in their natural sources. The proportion of 4:1:1 was examined by study and the results say that it increases protein synthesis in more than 30%. [33] That’s why we recommend you to reach for the products of BCAAs in proportion of 2:1:1 and 4:1:1.

The proportion of amino acids in BCAAs

The side effects of BCAAs

There aren’t known any side effects of BCAA supplements because they are the same substances which you can receive by means of protein nutrition. BCAAs can evoke a feeling of a full stomach only. [38]      

To conclude it, BCAAs have many positive benefits for the body. These benefits are used mostly by sportsmen who can achieve their fitness goals more quickly thanks to them. They help in muscle regeneration, protein synthesis, fat reduction and formation of the other effective substances.

What are your experiences with BCAAs? Write us which benefit of the BCAAs you appreciate the most and why. If you think this article can help people around you, support it by sharing.    


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