Do BCAAs Boost Muscle Growth?

Branched-chain amino acids (BCAAs) are a group of three essential amino acids; isoleucine, leucine and valine. Essential, meaning they cannot be produced by the body so must be gained through food. It is widely believed that BCAAs stimulate muscle protein synthesis to boost muscle growth and increase athletic performance.

Let’s take a look at the research to determine how true this notion actually is.

The role of BCAAs

BCAAs are located in muscle tissue and account for 21% of total body protein content. Skeletal muscles contain the largest amount of BCAA reservoir in the body. They are crucial building blocks for peptide synthesis and act as key nutrient signals and metabolic regulators.

An abundance of all essential amino acids (EAAs) is needed to stimulate muscle protein synthesis, however, BCAA supplementation alone has not been found to have a positive effect on muscle protein synthesis.

To build lean muscle, the rate of muscle protein synthesis must exceed the rate of muscle protein breakdown. Human studies revealed that intravenously infused BCAAs actually slowed the rate of muscle protein synthesis and muscle protein breakdown, leading to a decrease in muscle protein turnover. This is because without the presence of all other EAAs the rate of muscle protein synthesis is limited.

In contrast, some studies have found that BCAA supplementation before and after exercise decreased muscle damage and promoted muscle protein synthesis. However, a meta-analysis revealed studies showing a positive effect were lower quality studies compared to studies showing a negative effect. For this reason, further research is needed to determine the effectiveness of BCAAs on muscle growth.

Are BCAAs healthy?

BCAAs are found in protein-rich foods such as meat, eggs and dairy and are widely taken in powder form. Higher levels of BCAAs in the bloodstream are correlated with obesity, insulin resistance and accelerated ageing.

In a randomised control trial, it was demonstrated that a diet restricting BCAAs actually improved metabolic health, specifically glucose tolerance and body composition. Another study found an association between elevated levels of circulating BCAAs and obesity and the risk of developing insulin resistance in adults and children.

A study conducted on individuals consuming a diet high in BCAAs vs a diet comprised of no more than the recommended daily intake of protein found a significant increase in weight loss in the protein-controlled group, despite eating hundreds more calories per day.

Further, an imbalance of amino acids to BCAAs due to supplementation is correlated with hyperphagia, a disorder of excess appetite, and serotonin depletion, resulting in chronic fatigue and mood disorders.

If I still want to increase muscle growth without BCAAs, what are my other options?

Muscle growth is determined by a training routine emphasising hypertrophy, recovery and diet quality. There are also a variety of other supplements and herbs that have been proven safe and effective. You can learn about some of them here.

For specific recommendations, book an appointment. Together, we can explore your goals and needs to formulate a plan tailored specifically to you.

References

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