There are 20 common amino acids that make up the proteins that we recognise as the building blocks of life. These compounds are made from polymers of alpha-amino acids. These are amino acids formed from a molecule incorporating a carboxylic acid group (COOH) and an amino acid group (NH2).
There are over three hundred different types of amino acids that have been classified in nature so far. However, the compounds found in human peptides and proteins are made only from twenty different amino acids. There are several ways to classify amino acids. You can read more about these classifications here.
Below we have provided a brief introduction to the 20 common amino acids. You can find more detailed information about each amino acid in various articles on our website.
The 20 Common Amino Acids
Alanine: A non-essential amino acid, this compound was identified and replicated in laboratory long before it was isolated from natural sources.
This amino acid is found in high concentrations in a free state within human blood. It helps to boost immunity and energise the central nervous system, muscle tissue, and the brain by converting glucose to energy. Alanine also removes liver toxins.
Arginine: This amino acid was discovered in 1886 when it was isolated from a lupine seedling. Arginine has an important role in the immune system and cell division. It also helps to remove ammonia from the body, plus supports wound healing, and is involved in hormone release.
Arginine is perhaps most well known for its role as a precursor in the production of nitric oxide. Consequently this amino acid is very important for supporting a healthy circularity system.
Asparagine: This is the first amino acid isolated from its natural source. It was identified in 1806 from asparagus, hence the name. This amino acid is well known for its involvement in the biosynthesis of glycoproteins. It also helps to prevent fatigue and improves liver function. The human nervous system needs asparagine to maintain equilibrium.
Aspartic acid: Protein hydrolysis can produce this amino acid. It is required for stamina, immune function, neural and brain health. Aspartic acid also strengthens the immune system and helps with mineral transport.
Cysteine: One of only two sulphur containing amino acids, cysteine is a key constituent of important antioxidant glutathione. It helps to enhance white blood cell count to boost immune function.
Glutamic acid: A excitatory neurotransmitter, this amino acid is important for the central nervous system and is highly active in the brain and spinal cord. Necessary for healthy cell functioning, this is one of only a few nutrients that are capable of passing through the blood-brain barrier. It essentially helps to detoxify the brain by transforming excess ammonia into the amino acid glutamine.
Glutamine: This is a very active amino acid involved in many different metabolic processes. It is one of the most abundant free amino acids within plasma and muscles and is required for rapid cell division.
Glycine: Helping to regulate bile production, this amino acid is important for a healthy digestive system. It is also a central nervous system inhibitory neurotransmitter concentrated within the spinal cord, retina, and brainstem. It helps to construct normal RNA and DNA strands and safeguards against muscle wasting.
Histidine: This essential amino acid is needed to help regulate trace elements and is required for forming metal-bearing compounds and enzymes.
Isoleucine: One of three branched chain amino acids, this compound helps to elevate endurance and heal damaged muscle tissues.
Leucine: This amino acid is involved in protein synthesis, blood-sugar regulation, growth hormone synthesis, and supporting the growth and healing of bone tissues and muscles.
Lysine: Calcium absorption relies on the availability of this amino acid. Lysine is also involved tissue growth and recovery. It also is needed to produce antibodies, enzymes, and hormones.
Methionine: This sulphur containing amino acid acts as an intermediate in the process of producing different phospholipids in the body. It is very important in liver detoxification and single-carbon metabolism.
Phenylalanine: This amino acid is converted into another amino acid called tyrosine and joins to create adrenaline. Phenylalanine helps to support cognitive function and mental wellness.
Proline: The joints and tendons depend on proline for proper functioning as this amino acid is a vital component of collagen. Proline also helps to strengthen and maintain the cardiovascular muscles.
Serine: This amino acid is a precursor to many different amino acids and is involved with an array of biosynthetic pathways.
Threonine: Collagen, elastin, and enamel protein all contain threonine. This amino acid is also found in large quantities in the central nervous system and has been linked to treating various forms of depression. Threonine plays an important role in metabolism and digestion.
Tryptophan: This amino acid is a precursor to a range of important compounds including serotonin, niacin, and auxin. It is used widely in the treatment of conditions such as depression, insomnia, and anxiety.
Tyrosine: Healthy brain function requires this amino acid. Tyrosine helps to regulate concentrations of neurotransmitters such as noradrenalin and dopamine. It can help to reduce stress, and improve mental alertness.
Valine: Important for cognitive and smooth nervous system functioning, this amino acid also helps to supply the muscles with glucose for energy production. This amino acid is sometimes used to treat insomnia and anxiety.