BCAAs – Improving Muscle Mass, Promoting Weight Loss & Other Health Benefits

Branched-chain amino acids, commonly referred to as BCAAs, are amino acids characterised by a branched molecular structure. They include L-isoleucine, L-valine and L-leucine. These amino acids are vital building blocks for protein synthesis.
They are classified as essential amino acids because the body is unable to manufacture its own L-isoleucine, L-valine and L-leucine. This means that diet plays a vital role in order for the body to maintain an adequate concentration of BCAAs.

BCAAs promote muscle growth and recovery
BCAAs are particularly important for muscle growth, brain function and hormonal balance. The highest concentrations of these amino acids can be found within the skeletal muscle tissues. BCAAs help to increase energy, enhance endurance and assist with muscle tissue repair and recovery.

More specifically, L-leucine assists in regulating energy metabolism and protein turnover. This amino acid also plays an important role in inhibiting the breakdown of muscle protein which can occur after periods of high-intensity physical stress. L-isoleucine is important for regulating blood sugar levels, manufacturing hemoglobin and increasing energy. This amino acid also plays a very important role in muscle recovery. L-valine improves protein synthesis and energy metabolism. Like L-leucine, L-valine also helps to retain muscle strength during periods of high stress.

For these reasons, BCAAs are highly regarded by body builders and other athletes that require strong muscle tissue.

One of the differences between BCAAs and other essential amino acids in our body is the way they are metabolised. Most amino acids are metabolised in the liver, yet BCAAs are metabolised principally by muscles. L-leucine is broken down within fat pathways, L-valine is metabolised through carbohydrate pathways, while L-isoleucine is processed using both pathways. Because BCAAs are metabolised within muscle tissue, they can be immediately used as energy (oxidised) by muscle cells to generate ATP (adenosine triphosphate). ATP is a key energy source for muscle contraction and strength.

With increasing concentrations of BCAAs within the muscle tissue, there is also an increase in available energy. This reduces the breakdown of muscle cells and helps to prevent catabolism. Not only do BCAAs provide the body with energy, and strength through muscle growth, they also assist in muscle recovery and repair.

BCAAs help you exercise better for longer
While the unique metabolism of BCAAs provides an excellent energy source for muscle performance, BCAAs can also contribute to fat oxidation and a reduction in the body’s use of glycogen. This also enables individuals to exercise for long periods of time without fatigue because the energy demands are being met with relative ease. This applies to both endurance training and high energy training. Also, because glycogen is spared during the workout, the body is able to recover much faster and this can lead to a better training period the following day.

There has been a lot of research into the positive relationship between BCAAs and muscle building. One particular study followed the performance of trained weight lifters over two months. It revealed that participants who used a BCAA supplement throughout the training period gained twice as much muscle in comparison with those that didn’t consume the supplement.1 There are a number of factors that contribute to muscle gain in association with BCAAs.

The ability to train longer and harder with an optimal level of BCAAs has a positive influence on muscle building and body strength. BCAAs can directly increase muscle size by synthesising more protein, the foundation for muscle. L-Leucine is particularly important in this process because it stimulates protein production and boosts insulin levels. Insulin also further stimulates protein synthesis.

Research has also shown that BCAAs enhance growth hormones levels, contributing to an increase in muscle mass.2 Italian researchers discovered that athletes using BCAA supplements over a period of one month had elevated levels of growth hormone following workouts when compared to the control group. Higher levels of growth hormone can increase muscle size and enhance strength.

Another contributing factor to enhanced muscle building associated with BCAAs relates to cortisol. Cortisol is a catabolic hormone, often referred to as a ‘stress hormone’. High or prolonged elevated levels of cortisol have a range of negative impacts on the body, including the interference with testosterone. Cortisol can promote the breakdown of muscle tissue. Several studies have shown that BCAAs reduce the level of cortisol and promote a more favourable testosterone-corisol ratio.3 This reduces muscle breakdown and enables muscles to recover faster following exercise.

get fit and healthy with BCAAs
Not only can BCAAs help to increase muscle gain, they can also influence body fat. One of the first studies into the relationship between weight loss and BCAAs was published back in 1997.4 The research measured weight loss in competitive wrestlers while following a low-carb diet. Those wrestlers that took a BCAA supplement lost more weight than those taking a placebo. The most notable loss of body fat was around the abdomen. Similar results have been achieved in subsequent studies.5

Precisely how BCAAs assist with weight loss is yet to be determined. However, there are a number of theories. Increased protein synthesis stimulated by L-leucine may enhance energy use to the extent that body fat is removed. L-leucine is also an appetite suppressant. The body may burn more while eating less, consequently leading to weight loss. Other research has indicated that L-isoleucine supplements can reduce fat gain. 6. This may be because L-isoleucine actives PPAR receptors that are responsible for enhancing fat burning and reducing fat storage.

Clearly BCAAs have a positive influence on our body when it comes to muscle gain and weight loss. However, the benefits of these essential amino acids are not limited to these two functions.

  • Anti-aging: Recent research suggests that BCAAs may have some anti-aging properties. These amino acids have been shown to promote the formation of new mitochondria and consequently lead to increased energy production and rejuvenation.7
  • Liver protection: There is evidence that BCAAs can improve liver function and offer protection against liver diseases 8. For those patients already suffering from chronic liver problems, BCAA supplements may help to ease the symptoms and repair some of the damage.
  • Diabetes prevention: BCAAs have a strong association with insulin. These amino acids can enhance glucose tolerance and improve insulin sensitivity. They may play an important role in helping patients manage diabetes as further research develops.
  • Treating depression: An enhanced production of neurotransmitters and improved cognitive function can be gained through BCAA supplementation. Research studying the effects of BCAAs in the elderly population has shown that symptoms of depression can be reduced through BCAAs 9. Patients in this study that took BCAA supplements experienced improved muscle function, better nutrition and a more active lifestyle. These factors can contribute to a reduction in depression amongst the elderly.
  • Post-operative recovery: BCAAs can assist in muscle recovery following surgery 10. This is because they stop the muscle from breaking down during periods of immobility.

Grilled salmon, red meat, paultry and dairy contains lots of BCAAs
As the body is unable to manufacture BCAAs it’s important to eat BCAA rich foods. Protein rich food is the best source of L-isoleucine, L-valine and L-leucine, in particular, red meat. Poultry, raw salmon and dairy products are also recommended. Other good sources of BCAAs are walnuts and mais flowers.

Determining the necessary intake for optimal results can be confusing for many people. For serious body builders and athletes the recommended dosages are much higher than for an inactive adult. Body weight and age also have an impact on daily BCAA requirements. As we age, our body generally has a higher need for these amino acids.

For many people, it is necessary to complement a healthy diet containing BCAAs with powder and/or liquid protein supplements. There are a wide range of products on the market that are ideal for pre, during and post workouts. Whey protein shakes are particularly popular because they can be digested easily. Soy protein is also another option for those people who are lactose intolerant.

If you are uncertain of the appropriate BCAA intake for your lifestyle and body requirements, it’s a good idea to consult a health practitioner or nutritionist. They will be able to discuss your diet and supplement requirements based on your individual needs.

Here is a very useful video explaining BCAAs and their various benefits in detail:



When it comes to muscle growth BCAAs have a significant role to play. Essentially, they encourage growth and strength through several different mechanisms. They act as the building blocks to generate muscle protein and directly instigate the mechanism responsible for protein synthesis. This is further boosted by triggering insulin-driven protein synthesis, lowering cortisol levels and increasing growth hormone levels.

While the direct relationship between weight reduction and BCAAs isn’t clearly determine, there is enough evidence to suggest that these essential amino acids may have a critical role to play in limiting weight gain and promoting weight loss.

With potential anti-aging properties, protection against various diseases and other positive health benefits, BCAAs are a vital part of our well-being. Whether you are a serious athlete or just want to improve your health, incorporating a sufficient quantity of BCAAs in your diet can help you lead a healthy, active lifestyle.



Related studies:


  1. “http://www.jissn.com/content/6/S1/P12”
  2. “http://www.ncbi.nlm.nih.gov/pubmed/11310926”
  3. “http://www.ncbi.nlm.nih.gov/pubmed/21789887; http://www.ncbi.nlm.nih.gov/pubmed/20300014”
  4. “https://www.thieme-connect.com/ejournals/abstract/10.1055/s-2007-972594”
  5. “http://www.jissn.com/content/6/S1/P1; http://www.ncbi.nlm.nih.gov/pubmed/21872432
  6. “http://www.ncbi.nlm.nih.gov/pubmed/20089773”
  7. “http://www.cell.com/cell-metabolism/abstract/S1550-4131(10)00304-9
  8. “http://lib.bioinfo.pl/paper:21829025; http://europepmc.org/abstract/MED/21088568/reload=0;jsessionid=ch7yB9KMpy1p2sdbrOkx.16”
  9. “http://www.ncbi.nlm.nih.gov/pubmed/21636183”
  10. “http://www.ncbi.nlm.nih.gov/pubmed/12471043”