Essential Amino Acid: Definition & Explanations

Essentielle Aminosäure: Definition & Erklärungen

Amino acids make an important contribution to the proper functioning of our body. However, some of them, the essential amino acids, cannot be produced by the body itself. It is therefore necessary to ingest them with food. But which foods are the easiest to meet my need for essential amino acids and when does it make sense to take dietary supplements?

In our article on the essential amino acid you will receive all the important information about the effects, functions and absorption of these vital chemical compounds. We will advise you which foods are particularly good sources of amino acids and how high your requirement is. You will also learn what consequences a lack of essential amino acids can have and how you can recognize an undersupply.

the essentials in brief

  • In contrast to non-essential amino acids, our organism cannot synthesize essential amino acids itself. It is therefore important to provide the body with a sufficient amount of essential amino acids through protein-rich food.
  • Essential amino acids primarily serve as indispensable protein building blocks. In addition, they are required for the formation of diverse compounds and are involved in various metabolic processes.
  • The average daily requirement for essential amino acids can increase for certain people who put their bodies under heavy strain. In such cases, taking dietary supplements can be useful.

Glossary entry: The term essential amino acid explained in detail

You've come across the term essential amino acid, but aren't quite sure what it means? So that you are fully informed, we have summarized the most important questions about essential amino acids for you. You will learn which essential amino acids actually exist and what their functions are. We will also explain how you can cover the need for protein building blocks.

What are essential amino acids and why are they important?

A large part of our body is made up of amino acids - because amino acids are the basic building blocks of proteins, which in turn serve as building blocks for cells and tissue.

But the importance of amino acids in our organism is even more diverse: they are involved in cell renewal and enable the production of new energy. They are also involved in various metabolic processes as starting products for a wide range of compounds in the body.

Our body can produce (synthesize) some amino acids itself, while others have to be ingested through food. Since the latter are vital for the body, they are also referred to as essential amino acids.

Man ties shoelaces

Our body needs essential amino acids for regeneration and formation of new muscle tissue. (Image source: Alexander Redl / unsplash)

There are also amino acids that the body only needs to be supplied with through food under special circumstances, such as during growth. These are therefore only conditionally essential and are therefore referred to as semi-essential.

What are the essential amino acids and what are their functions?

8 amino acids are considered essential for the human body. A ninth amino acid, histidine, is often included among these. The adult body can produce it in limited amounts, but it is considered essential for infants.

In the following table you will find an overview of all essential amino acids (including histidine) and their functions in the organism.

Essential Amino Acid functions
lysine Lysine has a special function in the formation of proteins, especially structural proteins such as collagen. In addition, the amino acid is required for the synthesis of carnitine (1).
tryptophan Tryptophan is used as a starting material for the production of the happiness hormone serotonin and the sleep hormone melanin. This amino acid is also important for liver metabolism (2).
leucine Leucine is one of the three amino acids from the group of branched-chain amino acids (abbreviated BCAA). It plays an essential role in protein metabolism and in building and maintaining muscle protein. It also supports various healing processes in the muscle (3.4">.
valine Valine is one of the branched-chain amino acids and is therefore important for maintaining and building muscle protein. In addition, the amino acid is of great importance for proper nerve function (3.4">.
histidine Histidine is a direct precursor for the synthesis of histamine. In addition, the amino acid is important for the formation of non-essential amino acids (5).
isoleucine Isoleucine is the third branched chain essential amino acid. It is of great importance for the regeneration and formation of new muscle tissue and serves as an important source of energy in competitive sports (3.4">.
threonine The amino acid threonine is involved in strengthening the immune system: it supports the formation of antibodies and immunoglobulins (6).
phenylalanine Phenylalanine is required for the formation of non-essential amino acids and numerous hormones such as adrenaline and dopamine (7).
methionine Methionine is required for the formation of the protein-forming amino acid cysteine. In addition, the amino acid is involved in the synthesis of carnitine (8).

There are numerous aphorisms that can help you memorize all of the essential amino acids. For example, you can memorize these (including histidine) with the following mnemonic: "The Lys terne Trystan flees into the Val d and shows a phenomenal method to the His teric Isolde on the stairway ."

Please note that the spelling in this mnemonic has of course been adjusted so that the individual amino acids are easier to recognize.

Which foods contain essential amino acids?

In order to provide your body with enough essential amino acids, you should eat a healthy and balanced diet. Essential amino acids are mainly found in animal protein sources, but you can also get enough of them from purely vegetarian food.

The following foods contain a high proportion of several different essential amino acids:

  • Animal products: chicken eggs, meat (especially chicken), fish (especially cod) dairy products (especially cheese)
  • Seeds and Nuts: Flaxseeds, hemp seeds, chia seeds, walnuts, peanuts, cashews
  • Green vegetables: broccoli, spinach
  • Legumes: lentils, peas, soybeans
  • Cereals: rice, bran, buckwheat, oatmeal, quinoa

Note that not only the amount of essential amino acids, but also a balanced mix of all of them is important for a healthy body. In principle, animal products such as meat and dairy products contain sufficient amounts of all essential amino acids.

3 types of beans

You can get all 8 essential amino acids from food. Beans are a particularly good vegetable source of amino acids. (Image source: Tijana Drndarski / unsplash)

If you eat a purely plant-based diet, you can eat grains and legumes together, for example. Their amino acid profiles complement each other, so you can easily cover the average need for essential amino acids.

How many essential amino acids does your body need?

The average daily requirement of essential amino acids for an adult is around 0.18 grams per kilogram of body weight. This consists of the following recommended values ​​for the respective amino acids:

Essential Amino Acid Daily requirement per kg Daily requirement at 70 kg
lysine 30 mg 2100 mg
tryptophan 4 mg 280 mg
leucine 39 mg 2730 mg
valine 26 mg 1820 mg
histidine 10 mg 700 mg
isoleucine 20 mg 1400 mg
threonine 15 mg 1050 mg
Phenylalanine (along with tyrosine) 25 mg 1750 mg
Methionine (along with cysteine) 15 mg 1050 mg


The amino acids tyrosine and cysteine, which are listed in the table for phenylalanine and methionine, are semi-essential amino acids.

Please note that the average requirement for essential amino acids can differ for certain groups of people. The daily requirement is usually higher, especially after a muscle injury, during pregnancy, breastfeeding and in old age.

How do you recognize a lack of essential amino acids?

As soon as our body lacks a balanced mixture of all essential amino acids, certain vital bodily functions cannot function optimally.

Since the essential amino acids serve as building blocks for proteins, a lack of these can lead to an undersupply of the body's own proteins. In the long run, this can have various negative consequences for our health.

If the body is not supplied with enough essential amino acids to form the body's own proteins, it has to fall back on existing protein stores. Among other things, this can lead to deficits in muscle building, muscle reduction and a drop in performance (10).

To determine whether you have a deficiency symptom, you can have an amino acid analysis carried out. This indicates the existing amino acid concentration in the body.

In addition, an amino acid deficiency can manifest itself in an increased susceptibility to infections. When the body lacks the branched-chain amino acids (leucine, isoleucine, and valine), the amino acid glutamine cannot be synthesized adequately. Scientific studies indicate that low plasma glutamine levels can disrupt the immune system (11).

Since the symptoms of an amino acid deficiency are usually relatively inconspicuous and appear rather insidiously, they are very often overlooked. In general, however, the following symptoms can indicate that there is a lack of amino acids in your body:

  • Skin changes, severe hair loss, brittle nails
  • maturity
  • Performance Limitations
  • weight gain
  • increased stress, panic attack

For whom are preparations with essential amino acids useful?

If you pay attention to a varied and balanced diet, it is usually not necessary to supplement essential amino acids in isolation. However, in certain groups of people who, for example, put a lot of strain on their bodies, the protein requirement is often increased.

In such cases, it can make sense to take essential amino acids through dietary supplements. These come in different dosage forms, such as powder or capsules.

In the following paragraphs you will find out who is suitable for taking dietary supplements with essential amino acids.

competitive sport

Amino acid or protein supplements can be particularly useful for endurance and strength athletes. After all, intensive sport creates an increased need for protein, which cannot always be covered by protein-rich food.

woman jumping

Essential amino acids are absolutely necessary for a healthy and active life. (Image source: Peter Conlan / unsplash)

Some athletes use a preparation with a specific essential amino acid, others choose a combination of several protein building blocks. BCAA supplements are particularly popular, as they help build muscle and can have a performance-enhancing effect (12).

Low calorie diets

If you've tried a strict diet before, you may be familiar with the following scenario: you reduced your calorie intake, but the weight still didn't go down. One possible reason for this relatively common phenomenon is an amino acid deficiency.

During the diet, you probably didn't get enough protein into your body. As a result, your organism began to break down endogenous proteins in muscles. Because muscles play an important role in energy expenditure, having less muscle means you've burned less fat.

With a calorie-reduced diet, it is therefore important to provide the body with a sufficient amount of protein. Dietary supplements with amino acids can serve as a useful support.

stressful situations

In general, our body needs more proteins and protein building blocks in particularly stressful and stressful situations. Dietary supplements can be useful in order to cover this additional requirement in a targeted manner and more quickly.

The need for amino acids is also increased in diseases.

In addition, seniors should also ensure an adequate intake of protein building blocks. Because proteins are absorbed less effectively with age, the older body needs more protein building blocks to build muscle tissue.

However, it is important to mention that amino acid supplements are by no means preferable to a balanced and healthy diet. Only if it is not possible to cover the protein requirement with protein-rich foods should you consider taking dietary supplements.


In order to ensure a wide variety of vital body processes, our body must be supplied with a balanced mixture of all 8 essential amino acids. In addition to their function as protein building blocks, they take part in several metabolic processes and serve as important starting materials for other compounds.

Essential amino acids are mainly found in animal products, but they can also be obtained from purely plant-based foods. Cereals and legumes in particular are ideal here. For certain groups of people, such as competitive athletes, taking dietary supplements could be useful. However, you should only use supplements if you cannot cover your need for essential amino acids with a balanced and protein-rich diet.


  1. Singh, Meenu & Rao, Dowlathabad & Pande, Shivansh & Battu, Sowjanya & Rajeswar Dutt, Kunduri & Ramesh, Mantri. (2011). Medicinal Uses of L-Lysine: Past and Future. International Journal of Research in Pharmaceutical Sciences. 2.
  2. Richard DM, Dawes MA, Mathias CW, Acheson A, Hill-Kapturczak N, & Dougherty DM (2009). L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. International journal of tryptophan research : IJTR, 2, 45-60.
  3. Kim DH, Kim SH, Jeong WS, Lee HY. Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances. J Exercise Nutrition Biochem. 2013;17(4):169-180. doi:10.5717/jenb.2013.17.4.169
  4. Schena F, Guerrini F, Tregnaghi P, Kayser B. Branched-chain amino acid supplementation during trekking at high altitude. The effects on loss of body mass, body composition, and muscle power. Eur J Appl Physiol Occup Physiol. 1992;65(5):394-8. doi: 10.1007/BF00243503. PMID: 1425642.
  5. Holeček M. Histidine in Health and Disease: Metabolism, Physiological Importance, and Use as a Supplement. nutrients. 2020;12(3):848. Published 2020 Mar 22. doi:10.3390/nu12030848
  6. Feng L, Peng Y, Wu P, et al. Threonine affects intestinal function, protein synthesis and gene expression of TOR in Jian carp (Cyprinus carpio var. Jian). PLoS One. 2013;8(7):e69974. Published 2013 Jul 26. doi:10.1371/journal.pone.0069974
  7. Muhammad Akram, Muhammad Daniyal, Aatiqa Ali, Rida Zainab, Syed Muhammad Ali Shah, Naveed Munir and Imtiaz Mahmood Tahir (April 8th 2020). Role of Phenylalanine and Its Metabolites in Health and Neurological Disorders, Synucleins - Biochemistry and Role in Diseases, Andrei Surguchov, IntechOpen, DOI: 10.5772/intechopen.83648. Available from:
  8. Aledo JC. Methionine in proteins: The Cinderella of the proteinogenic amino acids. Protein Sci. 2019 Oct;28(10):1785-1796. doi: 10.1002/pro.3698. Epub 2019 Aug 9. PMID: 31359525; PMCID: PMC6739822.
  9. Joint FAO/WHO/UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition (‎2002 : Geneva, Switzerland)‎, Food and Agriculture Organization of the United Nations, World Health Organization & United Nations University. (‎2007)‎. Protein and amino acid requirements in human nutrition: report of a joint FAO/WHO/UNU expert consultation. World Health Organization.
  10. Mozanzadeh MT, Yaghoubi M, Marammazi JG et al. Effects of dietary protein and essential amino acid deficiencies on growth, body composition, and digestive enzyme activities of silvery-black porgy (Sparidentex hasta). Int Aquat Res 10, 45-55 (2018).
  11. Cruzat V, Macedo Rogero M, Noel Keane K, Curi R, Newsholme P. Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. nutrients. 2018;10(11):1564. Published 2018 Oct 23. doi:10.3390/nu10111564
  12. Stoppani J, Scheett T, Pena J, Rudolph C, Charlebois D. 2009 international society of sports nutrition conference and expo new orleans, la, USA. 14-15 June 2009. Abstracts. J Int Soc Sports Nutr. 2009;6 Suppl 1(Suppl 1):P1-P19. Published 2009 Jul 31. doi:10.1186/1550-2783-6-s1-p1
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