The Ultimate Guide to Essential and Non-essential Amino Acids

Amino acids can be placed in the category of either essential or non-essential. The name is self explanatory. Essential amino acids are those that are “essential” in the diet. In other words, we cannot create them through our own metabolism. Non-essential amino acids are those which can be produced from other amino acids and substances in the diet and metabolism.

Amino acids are important organic compound that help building proteins. In human body they’re second largest group of components after water. Amino acids are divided into two groups: essential and non-essential ones. Essential amino acids cannot be synthesized in human’s body, therefore they need to be obtained from food. Non-essential amino acids can be produced therefore it’s not necessary to provide them in food. Names may be misleading. Non-essential amino acids aren’t less important than the essential ones. It the need for obtaining them from external sources that makes them essential. In other words: it is essential to provide them from food, hence the name.

essential and non-essentail amino acids labelAs mentioned above, non-essential amino acids can be produced from other amino acids and substances. When there’s such need, metabolism can switch into producing amino acids required for synthesizing proteins needed at the moment. Non-essential amino acids: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine and tyrosine.


Essential amino acids cannot be synthesized, therefore when there’s no food the body relies on the amino acids stored, like albumins. Ultimately it will start using proteins from muscles – an effect highly unwanted by all bodybuilders and other athletes. Essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

Essential amino acids


It can be found in all body tissues. It is crucial for production of red and white blood cells. It takes parts in transmission of information between brain and other cells. It’s required for letting immune system know about allergic reactions and it helps producing gastric acids for correct digestion. Too low levels of histidine may help developing rheumatoid arthritis. Although produced by the body, the supplies run out pretty fast, therefore obtaining it from external sources is required. It can be found in meet, dairy, grains (wheat, rice, rye).


It’s a quite important amino acid in bodybuilding. It helps increasing endurance as well as repairing muscles. It’s a BCAA type of acid. It promotes recovery after workout and keeps energy levels stable. Good sources of isoluceine are: meet, eggs, fish, nuts, seeds, peas and soy.



It’s one of the BCAAs. Together with isoleucine and valine take part in muscles recovery. Leucine is the most effective being converted to glucose more quickly, what prevents from muscles cannibalism during workout. It helps repairing muscles, regulates sugar levels, increases production of growth hormone and burning fat. Sources of leucine are: brown rice, beans, meat, nuts, soy flour, and whole wheat.


essential amino acids   complexIt’s an amino acid known for its antiviral properties. It is involved in production of antibodies for stronger immune system and is required for production of hormone as well as growth and maintenance of bones. Due to its antiviral properties it can help fighting and/or preventing herpes and cold sores. It stimulates production of collagen and muscle protein what benefits in faster recovery. Good sources of lysine include red meat, cheese, eggs, fish milk, potatoes and yeast.


It helps processing and eliminating fat. Takes part in production of glutathione as well as cystenine and taurine, helping the body in eliminating toxins. It’s required for production of creatine, a substance improving muscles performance and endurance. It’s also crucial for the production of collagen for healthier skin and nails. People with allergies or arthritis may benefit from supplementation of this amino acid as it reduces histamines levels in the body. Sources of methionine: meat, eggs, fish, garlic, beans, lentils, onions, soy, seeds, and yoghurt.


It’s an essential amino acid required for correct functioning of central nervous system. As it can penetrate blood-brain barrier it is effective in treating brain disorders. This amino acid can also help control symptoms of depression and chronic pain. Some studies show that it can help curing vitiligo (white patches on the skin). Phenylalanine supplementation may improve memory and concentration as well as help in feeling happier. This amino acid has also been used to treat Parkinson disease and schizophrenia, however anyone wishing to try using it as a supplement shall contact their doctor first. Anyone with high blood pressure and/or migranes as well as v phenylketonuria (PKU) shall avoid this amino acid, by avoiding sources rich in it. Large doses of phenylalanine may cause nerve damage.


Crucial for the production of muscle tissue as well as collagen and elastine. Takes part in building strong bones and teeth (enamel). Promotes growth and protein balance in the body. Supports nearly all systems in the body: central nervous, cardiovascular and immune. It prevents liver from clogging with fats. With a correct, balanced diet, it’s rather hard to have theorine deficiency as it can be found in dairy foods, meat, grains, mushrooms and leafy vegetables.


Can be metabolised to niacin. It is used to synthesise melatonin and serotonin. Serotonine can help in regulating blood pressure and respiration. Providing high amount of serotonin can cause relaxation and improve sleep.


It’s one of the branched amino acids (BCAAs). It works with other BCAAs to support normal growth and repair tissues. It provides body with energy preventing muscles from breakdown and regulates sugar levels. It is needed for correct mental functioning. Valine can help liver to remove excess nitrogen and is able to transport it to other body areas where needed. Valine can also help treat liver and brain damage due to alcohol or drugs abuse. This amino acid shall always be taken in conjunction with other BCAAs: luceine and isoluceine. Natural sources of valine are: meats, dairy products, mushrooms, peanuts and soy protein.

Non-essential Amino Acids


It’s used as an energy source, as it helps the body to convert glucose into energy and can eliminate toxins from the liver. Helps preventing muscles from breakdown in so called alanine cycle, which can be simplified to: glucose – pyruvate – alanine – pyruvate – glucose. This cycle provides more energy increasing cell’s life. During this cycle excess nitrogen is removed from the body (urination). Alanine can reduce enlarged prostate symptoms. Sources of this amino acid are: meat, poultry, eggs, dairy products, fish and some plants, like avocado.


It’s one of the most important amino acids in humans body. It’s required to keep joints, liver, skin and muscles healthy. Due to its repairing properties it can be used by people suffering from arthritis and other joints problems. It also improves immune system by increasing T lymphocytes output. It helps processing creatine and nitrogen, substances that are crucial for every bodybuilder. It may also help reducing body fat and speeding up healing of damaged tissues. Although this amino acid is produced by the body, the supplementation can be considered especially by people fighting infections or burns and by people wishing to loose weight, improve immune system or build muscles. Natural sources of this amino acid are: meat, dairy products, wheat , chocolate, coconut, gelatin,oats, peanuts, soy and walnuts.


It’s closely related to aspartic acid. It is required by the nervous system. The body also uses this amino acid in synthesis of ammonia. Asparagine can be found in both animal and plant sources: beef, poultry, whey, eggs, fish, dairy, asparagus, potatoes, nuts seeds, whole grains.

Aspartic acid – also known as L-aspartate


It can help improve metabolism and take part in sythesis of other amino acids like arginine, lysine and isoluceine. Aspartic acid is crucial for producing cellular energy, by taking part in generating adenosine thriphosphate (ATP) the ultimate fuel that drives all cellular activity. It also support brain due to increasing concentration of NADH, a substance that boosts production of neurotransmitters and other substances required for correct brain functioning. Although this amino acid can produced by the body, it can also be found in: poultry, dairy, beef and sugar cane. It can also be bought as a supplement.


It can be found in beta-keratin, the most abundant protein in skin, nails and hair. Most easily absorbed form of cysteine is N-acetyl cysteine (NAC). It may be effective in treating cancer, bronchitis, smoker’s cough, heart disease or septic shock. This amino acid is the body however it can be provided from meat,, eggs, broccoli, onions, garlic and red peppers.

Glutamic acid – also known as glutamate


It’s the most important excitatory neurotransmitter in the brain and spinal cord. It takes a vital part in sugars and fats metabolism and helps in transportation of potassium into the spinal fluid and through blood-brain barrier. Glutamic acid may be used by brain as fuel. It can be transformed into glutamine or GABA.


It helps build and maintain muscles and remove toxins from liver. It can cross blood-brain barrier and, after being transformed into glutamic acid, can work as fuel for brain. It can also increase GABA levels. This amino acid is an important source of energy for nervous system. L-glutamine supplements are mainly used for bodybuilding, however users report more energy and overall better mood. Glutamine synthesised from nitrogen and glutamic acid help eliminating toxic ammonia from the liver – nitrogen isn’t converted into it.

Glutamine also helps transporting nitrogen to other areas, especially muscles, where it helps topping up glycogen supplies. It is important as it prevents muscles breakdown. Up to 60% of amino acids content in muscles is glutamine. It is also important for immune system and may help treating rheumatoid arthritis, chronic fatigue or scleroderma. Glutamine can be found in many foods, however it is easily destroyed during cooking process. Parsley and spinach eaten raw are good sources of this amino acid. Read more.


This amino acid helps in creating muscle tissue. It also aids in transformation of glucose into energy. Increases creatine levels, what helps in building muscle mass. Nearly 30% of collagen is made of glycine. In fact, without this amino acid the body wouldn’t be able to heal wounds and other damaged tissues. Good sources of glycine are high protein foods like fish, meat, milk, beans or cheese.


It’s an amino acid needed for production of collagen and cartilage. It stimulates collagen production which then helps in rebuilding cartilage, therefore it may be beneficial for individuals suffering from damaged joints. This amino acid is useful for recovery after injuries, like burns improving healing process. Good sources of proline are: meat, dairy and eggs. Vegetarians shall take supplementing of this amino acid under consideration.


It’s main role is supporting correct functioning of the brain and the central nervous system. Proteins building brain and its protective cells contain this amino acid. It also takes part in making serotonin, a chemical having significant impact on the mood. It also takes part in metabolism of fats and fatty acids and helps in absorption of creatine. Meat, dairy products, wheat (gluten), soy and peanuts are examples of good sources of this amino acids.


This amino acid helps in normal functioning the whole body. It can help regulating appetite and its low level can result in low pressure, slow metabolism and tiredness. It can also assist in production of neurotransmitters, which have a significant influence on human-environment interaction.


Amino acids can have significant impact on the body. Supplementation may be beneficial, but sometimes may bring adverse effects. Please make sure you consult a qualified person (a doctor, a nutritionist etc) before you start providing additional amino acids. I’s very important, as you may have some hidden medical conditions which the supplementation of amino acids may aggravate. Additionally some of those amino acids can be manufactured in the body and some are already provided with food, therefore it is crucial to determine that increased levels are needed. Please note that amino acids available on the market without prescription are generally considered as safe.