This month we’ve been looking at amino acids, what they are & how they affect recovery because they’re pretty important for athletes. Now its time to find out how amino acids affect muscle growth. Keep reading to find out more!

Top amino acids for muscle & strength

As mentioned in our previous posts Why Amino Acids Are Better Than Protein Supplementsand Amino Acids + Recovery: What’s The Deal, amino acids have many benefits for athletes. However there are several amino acids that are better known for their ability to build muscle & increase strength than others, including:

· BCAAs (branched-chain amino acids L-leucine, L-isoleucine and L-valine) for muscle tissue growth and repair,

· L-arginine for improvement of blood flow

· L-carnitine for fat burning and faster recovery

· L-glutamine to increase water retention in the muscle cells and to assist in signalling cell growth

What is hypertrophy?

Using a variety of training methods, athletes are able to achieve muscle hypertrophy. Hypertrophy is an increase in the size of a muscle which is caused by an increase in the size of the component cells that make up that muscle.

To explain in further detail; when you begin exercising a muscle, there is an initial increase in the nerve impulses that cause that muscle to contract. This will increase strength but it won’t change muscle size.

However, as you continue to exercise there is a complex interaction of nervous system responses that will increase protein synthesis over the coming months, and as a result your muscle cells will grow larger and stronger.

In other words, there are two essential components that are needed for muscle growth – stimulation and repair. Stimulation happens through contraction of the muscle repeatedly which in turn will cause damage to the muscle fibres, while repair which occurs when new muscle fibres are produced to replace or repair the damaged ones. When this stage happens, this is when muscle growth really takes place.

Amino acids are particularly effective in growing and repairing muscle tissue because they are the building blocks of protein and without these amino acids the body cannot energise the muscles.

Why you need to be getting enough amino acids

If you are not meeting your body’s nutritional needs, your body will start to break down muscle tissue in order to repair the tissue damaged during your training session. As a result, you’ll suffer atrophy (a reduction in your overall muscle mass.) And no one wants that!

As an athlete you generally have a more muscular body, making it even more important that you meet your nutritional needs as you will consume more energy, even at rest.

Supplements for increased muscle growth

Several of the nutrients that are required to build muscle mass are also essential, meaning the body cannot produce them itself. Although these nutrients can be absorbed by foods, it is often more efficient and effective to consume them in larger quantities via dietary supplements.

There are many supplements out there than can support muscle growth but its about choosing the correct supplement for your needs. Protein products help to increase muscle mass and strength in the short to medium term which is why athletes and bodybuilders frequently consume foods and supplements high in protein. Amino acids however, are used to build muscle and produce impressive results in a completely natural way.

Let’s look more closely at each of the amino acids & how they impact muscle growth:


Branched-chain amino acids (BCAA’s) are especially important in building muscle as they dramatically improve the body’s ability to synthesise protein and as a result, build muscle mass after supplementing of just two weeks (4 grams three times daily.)

BCAA’s are a key nutrient for muscle repair as they aid protein synthesis through an increase of cellular capacity. In simple terms this means that your body is now more able to repair itself. BCAA’s also go directly to your skeletal muscles reducing the amount of protein breakdown that happens within your body.

Not only are BCAA’s good for muscle building and muscle repair, they also play an important role in the transport of oxygen to the muscles. Depending on the level of exercise, your muscles need large amounts of energy, as well as a sufficient amount of oxygen.


Taurine positively affects muscle growth and increases performance through it’s ability to reduce oxidative stress (tissue breakdown) following intense exercise.

When skeletal muscle is heavily strained, the body naturally builds free radicals which in turn can damage the cells in the muscle tissue. By supplementing with Taurine, you will prevent the production of superoxide-anions and therefore reduce the oxidative stress on the muscle tissue. This reduction of oxidative stress further results in an overall improvement in muscular performance.


L-arginine is an amino acid well-known to muscle and strength builders. By taking arginine blood flow and the effectiveness of the immune system increase however there are no clinical studies on how L-arginine itself influences muscle hypertrophy.


L-Carnitine is probably the most well-known amino acid in sport. L-carnitine transports fat molecules into the mitochondria (the cells power plant) which then converts these fat molecules into energy. By consuming additional carnitine you are decreasing the chance of your body breaking down muscle tissue to produce nutrients and energy. L-carnitine is therefore an essential component of an athlete’s nutritional plan.


Glutamine is the most common amino acid found in your muscles – over 61% of skeletal muscle is Glutamine. Glutamine consists of 19% nitrogen, making it the primary transporter of nitrogen into your muscle cells. During intense training, Glutamine levels are greatly depleted in your body, which decreases strength, stamina and recovery and it could take up to 6 days for Glutamine levels to return to normal! The benefits of taking L-glutamine are:

· Protein synthesis – It prevents your muscle from being catabolised (eaten up)

· Replenishes the declining Glutamine levels during intense workouts

· May serve to boost your immune system. This is important for those who lift heavy weights as heavy workouts tend to greatly deplete Glutamine levels as it is a primary energy source for your immune system.

· Glutamine is one of the most important nutrients for your intestines


Many studies have shown the importance of taking amino acids as they are the building blocks of the protein which makes up muscle tissue and therefore supports your body’s ability to build muscle naturally.

As an athlete your body needs much more energy and nutrients due to the amount of strain your body goes through as you exercise. By taking amino acids 20-30 minutes before any training or gym session, you’re ensuring that these amino acids are readily available for transportation to the muscles.

The human body adapts to training quickly, and over longer periods of time this improves the efficiency and the effectiveness at which your muscles deal with the demands of intense training. As a result you will have an increased ability to perform at high levels!

Related studies:

Casperson SL et al.: Leucine supplementation chronically improves muscle protein synthesis in of older adults consuming the RDA for Protein; Clin Nutr. 2012 Feb 20

Silva LA et al.: Taurine supplementation decreases oxidative stress in skeletal muscle after eccentric exercise; Cell Biochem Funct. 2010 Dec 27