An inside look at the role amino acids play in muscle growth, recovery and training

Amino acids, and derivatives of such, are right at the top of the list when it comes to sports nutritional products that have not only stood the test of time, but also delivered bona fide results in scientific clinical settings. They have been studied at length in research circles with respect to their ability to help enhance muscle growth, recovery and athletic performance. Before we get into all that though, a little background information on exactly what amino acids are is a good idea.The ABCs Of Amino Acids_feat


You’ll often hear (or read) that amino acids are the building blocks of protein. What does that really mean though? Essentially, amino acids are ‘organic’ compounds that join to form larger, whole protein molecules. When these whole proteins are eaten and ultimately digested, the body breaks them down and what’s left are the individual amino acids, which are vital for a whole slew of important bodily functions, not the least of which include growth and repair. Amino acids have traditionally been classified into three distinct groups:

  • Essential Amino Acids
  • Non-Essential Amino Acids
  • Conditionally Essential Amino Acids

Essential amino acids, as their name implies, cannot be made by the body, and as such, we need to ingest these via food and/or supplements. Non-essential amino acids on the other hand do not need to be consumed per say, given that the body has the ability to manufacture these amino acids on its own. And finally, conditionally essential amino acids are titled as such because they become important and are deemed ‘essential,’ during times of illness, disease and/or heavy stress. The chart below highlights the 22 standard amino acids that belong in each of these three categories. Now that we have a solid understanding of exactly what amino acids are and how they’re classified, we can get into the nitty gritty of some specific amino acids, and how they can help you achieve your physique and performance goals.

Branched Chain Amino Acids

Branched chain amino acids, a.k.a. BCAAs, are the essential amino acids Leucine, Isoleucine and valine. They are labelled as ‘branched chain’ because of their chemical structure, and have been used for years by physique athletes for the express purpose of improving training performance and decreasing muscle breakdown during exercise. In a study published in the International Journal of Sports Physiology & Performance, researchers found that subjects supplementing with Leucine daily experienced ‘significantly higher’ strength gains over the course of a 12-week resistance training program, as compared to subjects taking a placebo.

In another study published in the Journal of Sports Medicine & Physical Fitness, BCAA supplementation, as part of an intensive training program, ‘effectively’ reduced both fatigue and muscle soreness; with researchers theorising that these positive changes could likely be due to decreases in muscle damage and inflammation. At this point, you’re probably wondering what makes these BCAAs so special. Well, aside from their chemical structure, their big calling card is the fact that they are metabolised in muscle, rather than in the liver; and as such, they can be used for protein synthesis, provided of course that you’re in a well-fed state. So, from improvements in training performance, to heightened recovery, to increased protein synthesis, the science says BCAAs deliver.



Glutamine, the most abundant of all the amino acids in the body, is technically classified as ‘conditionally essential’.  And with that often comes the question, ‘if it’s not essential, why do I need it?’

Well, to answer that, we need to return to our definition. Remember, a conditionally essential amino acid is one that becomes essential during times of illness, disease and/or heavy stress. The key part of that for our purposes is the word ‘stress.’ If you’re lifting weights anywhere from three to five times a week and are hitting the compound movements hard and heavy, while also doing your requisite cardio, I have news for you, you’re under some serious stress, and if your diet is not spot as a means to match those training demands, then it’s only a matter of time before you suffer from a bad bout of overtraining, or worse, get injured.

As such, your body may likely need more glutamine than it can produce on its own. What’s also very important to keep in mind when it comes to glutamine is the fact that two thirds of all the glutamine in your body is stored in muscle tissue. During times of intense training these stores can become depleted, which can compromise training performance and physique pursuits. Enter glutamine supplementation. Supplementing with glutamine can help prevent this and promote a state conducive to anabolism,which is one of the main reasons why so many physique enthusiasts have turned to this amino acid over the years, and it has received so much positive, anecdotal praise in the bodybuilding community.


Arginine is another conditionally essential amino acid that has caught on like wildfire in the bodybuilding community over the last five years or so. If you’ve taken any one of the many effective pre-workout supplements on the market, you’ve likely taken arginine in some form or another, as this is often one of the main ingredients in this category of products. What makes arginine so unique is the fact that it acts as the precursor to nitric oxide, a vasodilator in the body that widens blood vessels, allowing for an increase in blood flow. The ability of arginine to help promote increased blood flow, and even the delivery of nutrients to muscle tissue, can result in better and more productive workouts in terms of overall strength increases, rep range increases and of course, some serious muscle pumps!


Tryptophan is an essential amino acid that is key for two important reasons; one, it is needed for proper nitrogen balance and two, the body uses this amino acid to make Serotonin, the body’s feel-good hormone. The logic behind supplementation with tryptophan is the fact that it raises tryptophan levels in the brain, which stimulates conversion to serotonin, as a means to help foster improved mood and/or better sleep.

Beta Alanine

Beta Alanine is one of the newer age supplements on the market that has a lot of people talking. In a very recent study published in the International Journal of Sports Nutrition & Exercise Metabolism, researchers found that supplementation with Beta Alanine improved punch force and punch frequency in a group of amateur boxers, and went as far as to say that these results may also follow suit in other combat sports. In another study, conducted on physical education students this time and published in the International Journal of Preventative Medicine, beta alanine supplementation led to a significant increase in VO2 max, prompting researchers to conclude that it can indeed improve exercise performance. What’s the secret to beta alanine’s success you ask? Simple, it increases carnosine levels in muscle. More carnosine in muscle means more efficiency with respect to buffering protons, which thereby helps delay fatigue, while fostering improvements in strength and muscular endurance.


And that’s that, a closer look at amino acids in general, and the impact a few of the more popular amino acids have on training performance and physique pursuits. Please keep in mind that there are many amino acid products and amino acid derivatives available on the market; some sold individually and others as part of multi-dimensional formulas. Amino acid products are available in capsule form, pill form, powder, liquid and some protein bars and protein powders are even fortified with additional amino acids. Talk about a versatile category!



  • Histidine
  • Isoleucine
  • Leucine
  • Valine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan

  • Alanine
  • Asparagine
  • Aspartic Acid
  • Glutamic Acid

  • Arginine
  • Cysteine
  • Glutamine
  • Tyrosine
  • Glycine
  • Ornithine
  • Proline
  • Serine
  • Taurine


Source: Beck, C. (2013, March/April). The ABC’s of Amino Acids. Inside Fitness, 102–104.