Amino acids are foundational molecules that play a very key role in human and animal physiology. When you are deficient in a certain amino acid due to dietary restriction or metabolic problems it can lead to very serious health issues. This article discusses the importance of several crucial amino acids.

All amino acids play an important role in the various processes of the body but some play a larger role than others. We could discuss every single one of these key molecules but in this article we will feature methionine, taurine, cysteine, arginine, tryptophan, lysine and glutamine.


Methionine is a key amino acid that brings methyl groups and sulfur into the body. It is an essential precursor for the formation of cysteine, glutathione, taurine and contributes to the formation of insulin and coenzyme A.

Methionine metabolism is subject to many impairments, resulting in a variety of disorders, including cardiovascular disease, neural tube defects, osteoporosis and neuropsychiatric disorders.


Taurine promotes potassium retention and research is showing that it has the ability to reverse cardiac abnormalities induced by cardiac glycosides or epinephrine. Full-term infants have minimal capacity to metabolize methionine. Mother’s milk is high in taurine, while cow’s milk contains only trace amounts.


This sulphur-based amino acid is a key part of methionine metabolism and it forms disulfide linkages in and between protein chains. It reacts with vitamin B5 and forms coenzyme A that serves as a precursor of taurine and it is the rate-limiting component of the powerful anti-oxidant glutathione (GSH).

This helps activate cytotoxic T cells, stimulates T cell proliferation in response to mitogens, and differentiates T and B lymphocytes. Cysteine is also critical for the detoxification and excretion of various toxins and protecting the cellular structures from oxidative stress.


This assists the transfer of amino groups by forming the linkage between transaminase enzymes. This is a critical part of the metabolic process which the body is unable to function without. Lysine improves intestinal calcium absorption and improves kidney calcium conservation.

It is also essential for the formation of carnitine and the utilisation of fatty acids for energy in the cells and is needed for proper immune function. L-lysine supplementation has been shown to improve immune system function and enhance thymus growth.


This helps the body excrete growth hormone and prolactin as well as the pancreatic secretion of insulin and glucagon. Arginine helps in the production of nitric oxide and enhances collagen formation. Both of these functions are key for cardiovascular function by improving blood flow and blood vessel integrity.

Research has linked arginine supplementation with reduced intimal thickness and vascular reactivity in atherosclerosis. It also helps to decrease platelet clumping and clot formation within the arterial walls.


This is the major precursor for the formation of serotonin which plays a huge role in mood regulation, pain regulation and sleep. Low tryptophan levels can result in mood disorders, chronic pain and insomnia. Serotonin forms melatonin which induces restful sleep. Melatonin is also a powerful anti-oxidant and immune modulating agent.


This is the most abundant amino acid in the bloodstream. In the cells, glutamine plays a very important role in the Krebs cycle and formation of energy. Glutamine is important for the maintenance and repair of gastrointestinal musosal integrity.

When glutamine stores are deficient it can lead to gut atrophy, gut-related inflammatory stress and small intestinal bacterial overgrowth. High doses of glutamine have been shown to prevent mucosal atrophy and bacterial translocation in cases of small intestinal bacterial overgrowth.