What are Non-Essential Amino Acids? It’s Types?

As we discussed previously, non-essential amino acids are by default synthesized by the body, thus, there is no need to consume them from other sources. However, in case of deficiencies or when the body’s production is not sufficient to match the requirement, they can be supplemented.

In our bodies, they perform a wide variety of functions like glutamine and arginine, for example, can regulate gene expression and cell signaling pathways, respectively. Other help to control the digestion and absorption of nutrients.

There are 11 Non-Essential Amino Acids which are enlisted below (click a name to scroll):

Food Sources

Even though these are synthesized by our bodies, still they can be obtained from the following foods;

  • Beef
  • Poultry
  • Fish
  • Dairy
  • Soy
  • Quinoa
  • Buckwheat
  • Nuts
  • Seeds
  • Beans
  • Some grains

It is utilized by the body to make proteins, break down other amino acids such as tryptophan, and transport vitamins such as Vitamin B6. It ensures proper transfer of nitrogen from around the liver, to metabolize glucose which in turn improves energy levels. Alanine also detoxifies the body and contributes to the production of antibodies by the immune system.


Arginine improves the immune system which in turn prevents the occurrence of diseases. It helps in the detoxification of the liver, whether alcohol-related toxins or metabolites of drugs. It also participates in the urea cycle, a detoxifying process through which the body gets rid of metabolic waste produced during the catabolism (breakdown) of amino acids.

Arginine is a biological precursor of Nitric Oxide (NO), the primary vasodilator in our bodies. That means appropriate consumption (or supplementation of L-Arginine) can improve our blood pressure and increase blood flow to various parts of the body. For this reason, it has been reported to improve symptoms of erectile dysfunction and increased exercise performance due to faster clearance of lactic acid as well as faster oxygen supply. Arginine is also a conditionally essential amino acid.


It is a derivative of aspartic acid that only has an additional amide group in its structure. It plays an important role in the synthesis of proteins and glycoproteins.

One of the main functions of asparagine is to break down and excrete ammonia from the body as it actively participates in the urea cycle. It is also used as an active ingredient in a variety of cosmetic products due to its capability to improve hair and skin health.

Aspartic Acid

It is mainly involved in metabolism, detoxification of the body, optimizing hormones (increases testosterone), and building and maintaining muscle mass. It is perfect for endurance athletes since it increases stress resistance and reduces chronic fatigue.

Aspartic Acid is effective against mental ailments such as depression.


It is involved in anabolic processes such as protein synthesis and various metabolic functions. It is a component of beta-keratin (a protein present in nails, hair, and skin) and important for making collagen. Cysteine protects the organs from the harmful effects of substances found in alcohol, tobacco, and drugs in general, as well as prevents the hardening of the arteries and rheumatoid arthritis.

Cysteine is also a precursor form of Glutathione, one of the most important antioxidants in our body, that clears out toxins and oxidized products from our body. It also enhances the effects of vitamins E and C. Cysteine is also a conditionally essential amino acid.

Glutamic Acid

Glutamic acid is primarily used to form proteins. It converts to glutamate in our body which acts as a neurotransmitter. It then stimulates the brain cells, spinal cord, and nervous system, enhancing learning ability and memory.

Glutamic acid is also involved in certain aspects of metabolism, as it metabolizes fats and sugars and helps to transport potassium. It is also a significant contributor to good skin health, as it maintains the pH balance of the skin, binding water molecules within the skin, and ultimately moisturizing it.


Glutamine is another example of a conditionally essential amino acid. Even though our body regularly makes it, the amount made may not be sufficient for events of high stress, such as during strenuous exercise or an injury.

Being one of the most abundant amino acids that our body produces, it has a very profound effect on athletes and sportspeople. Moreover, glutamine is often supplemented to maintain the acid-alkaline balance in the body and for ailments such as prevention of cancer, sickle cell disease, and burns, to improve recovery after surgery, for injuries, and complications of HIV/AIDS. Glutamine is also a conditionally essential amino acid.


Glycine, a proteinogenic (protein-creating) amino acid, facilitates glycogen storage (especially in skeletal muscles), slows down the deterioration of muscles, as well as strengthens the nervous system and immune systems.

It has been shown to contribute to good prostate health and is supplemented to treat Benign Prostate Hyperplasia (BPH). Glycine is a part of the collagen structure, improves healing, and most importantly, protects kidneys from damage induced by certain drugs or alcohol. Glycine is also a conditionally essential amino acid.


Proline contributes to protein synthesis and metabolism of compounds such as arginine, polyamines, and glutamate. It helps to produce collagen which means it is vital for good skin health. It acts as an antioxidant and usually works with Vitamin C synergistically to keep the connective tissues healthy. Also, proline is one of the major contributors to bone and cartilage integrity.

Proline is also a conditionally essential amino acid.


Serine, in its structure, has an alcoholic group (-OH) which enables it to metabolize fatty acids, fats, and cell membranes. It has critical importance for the growth of skeletal muscle tissue as well as the maintenance of the immune system because it helps in the production of antibodies. L-serine is an essential component of phosphatidylserine, which itself is a component of neurons, thus, improving brain function. It also protects the nerve fibers and enables the efficient functioning of RNA and DNA.

Serine is also a conditionally essential amino acid.


Tyrosine is a derivative of Phenylalanine, which plays a crucial role in the production of neurotransmitters since it is the precursor of dopamine, epinephrine, and non-epinephrine. These neurotransmitters are responsible for mood regulation, and their optimum production due to tyrosine causes improvement in depression, anxiety, narcolepsy, and insomnia.

It regulates thyroid hormones such as triiodothyronine (T3) and thyroxine (T4). These hormones regulate metabolic processes and in turn, help aid weight loss including fat loss. Tyrosine is also a conditionally essential amino acid.

What are Conditionally Essential Amino Acids?

Conditionally Essential Amino Acids (or Conditional Amino Acids) are those non-essential amino acids, that become essential in certain situations, such as during an illness, stress, or pregnancy.


About the Author

Muhammad Usman

Administrator, and Contributor at KeepUpFitness.

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