Your Guide to BCAA’s

What are they?

Amino acids are the building blocks of nature, they form proteins and are therefore responsible for the building and repairing of cells, tissue and internal organs. Branched chain amino acids are three of these amino acids: leusine, isoleucine and valine. They are essential amino acids which means that unlike non-essential amino acids which our bodies can produce, essential amino acids must come from an external source, i.e. from food or a food supplement because of our inability to synthesise them. 

Why do we need them?

Branched chain amino acids (BCAA’s) are essential for athletes and anyone involved in high intensity exercise. They are the most important amino acids when it comes to building muscle building proteins, in fact BCAAs make up approximately 1/3 of the bodies skeletal muscle! This is because they are metabolized in muscles rather than in the liver which is where the other amino acids are metabolized. 

BCAAs are crucial when you are involved in high intensity exercise, such as a heavy weights session or a particularly hard cardio session, and having a supply of branch chain amino acids can be of great benefit to you. When you exercise, your body’s glycogen store quickly depletes which causes protein synthesis to stop, which means your body is then in a catabolic state (not ideal). Introducing BCAAs, however, will mean that during high levels of stress on the body, for instance during rigorous exercise. Your body will continue its protein synthesis, meaning increased lean muscle gains and faster recovery between training sessions.

Another way that BCAAs can help to increase performance levels when it comes to exercise is that they can increase energy levels. When the body needs energy it can break down the muscle and extract the BCAAs to use as fuel. Therefore, having a good supply of BCAAs will mean that your energy levels are maintained and kept high during exercise. Muscle breakdown is a natural part of metabolism and is inevitably going to happen during exercise. But if you supplement your diet with BCAAs during or after exercise, you will help to spare muscles from being broken down so that you do not lose muscle mass.
Branched chain amino acids have also been shown to reduce fatigue because of their ability to reduce serotonin levels. Serotonin levels increase during exercise and in doing so tire us out. Increasing your amount of BCAAs, however, will help to reduce the onset of fatigue so that you can maintain a high level of performance throughout your period of exercise. 

So we’ve heard that branched chain amino acids are essential for building muscle and improving and enhancing performance, now let’s take a look at the three BCAAs individually to understand how each of them can be of benefit to you. 

The breakdown


Leucine is important for building and increasing lean muscle mass. It increases insulin secretion for better uptake of protein and carbohydrates, essential ingredients in the building of muscle and providing energy for the body. It is the most effective BCAA for preventing muscle loss because it can be broken down and converted to glucose more quickly than isoleucine and valine. This increase in glucose supply helps prevent the body’s catabolization of muscle for energy. Leucine also aids in the production of growth hormone, which can help to heal bones and skin, and also speed up recovery after exercise. For these reasons, leucine is often recommended for patients who are recovering from injury or surgery. Deficiency in leucine can lead to headaches, fatigue and even depression.


Isoleucine is essential in stabilising and regulating energy and blood sugar levels and is needed for haemoglobin formation. Its primary function is to boost energy and help the body recover from strenuous activity. Studies have shown that isoleucine can help to prevent muscle and tissue breakdown overnight, and during extreme levels of exercise such as marathons and other extreme distance events. Deficiencies in isoleucine can result in dizziness, confusion and irritability.


Valine helps the body to maintain a good nitrogen balance in the body, allowing muscle growth. Because of its ability to remove potentially toxic nitrogen from the liver, it is thought that valine can be used to help treat the liver as well as other organs that have been damaged by alcohol abuse. It also aids in muscle metabolism and tissue repair, and is therefore great for recovery from strenuous exercise. Valine helps to prevent the breakdown of muscle by supplying the muscles with extra glucose for energy production during intense physical activity. Another benefit of valine is that it helps to stimulate the central nervous system, helping the functioning of the brain.

Where can I find them?

Branched chain amino acids, as well as the other essential amino acids, are found in protein rich food, such as meat, fish and eggs. For the vegetarians among you, eating nuts, seeds and beans on a daily basis should make up for the lack of animal proteins in your diet. Ensuring that your diet is full of these kinds of food should provide your body with a healthy supply of all the amino acids, including the BCAAs. 

Supplementing your diet with BCAA powders and capsules might be something to consider if you are involved in a rigorous exercise programme and you do not want to lose muscle mass, or if you are interested in gaining lean muscle mass. As we have seen, a healthy supply of BCAAs can prevent the breakdown of muscles during exercise and can help increase muscle mass by increasing protein synthesis during exercise. So taking a BCAA supplement is a great way to keep your reserves topped up. It is possible to take separate supplements of each of the three branched chain amino acids or they can be taken in an all in one combined form.

Be aware, however, excessive amounts of branched chain amino acids can have detrimental effects on your health. It is thought that too much leucine and valine in the diet can lead to impaired liver and kidney function, increased ammonia in the body and the possibility of hallucinations. Like all supplements, be clear what you are putting into your body, and remember that they are supplements not substitutes for food!