The 20 Amino Acids: How Many Of Them Are Essential?

AminoAcidProducts | June 30, 2021 | Amino Acids

Amino acids are vital nutrients needed by the body for numerous functions. There are 20 classified amino acids required by the body, but of the 20 amino acids, how many are essential? Plus, what are the functions of the said essential amino acids?

Overview: Amino Acids

Protein’s building blocks are known as amino acids, which are compounds that play a crucial role in the body. Amino acids are required for the synthesis of neurotransmitters and hormones as well as the production of proteins. Furthermore, amino acids are categorized as non-essential, conditionally essential, and essential. For now, it’s all about learning what the essential amino acids are.

Essential Amino Acids

Valine, tryptophan, threonine, phenylalanine, methionine, lysine, leucine, isoleucine, and histidine are the nine essential amino acids. Unlike non-essential amino acids that are naturally produced by the body, essential amino acids come from the food one consumes. Excellent sources of essential amino acids include animal-sourced food such as poultry, eggs, and meat.


Listed below is a detailed look into the essential amino acids and their functions in the body.

  1. Histidine: This amino acid helps in the production of histamine, which is a neurotransmitter crucial in sleep-wake cycles, sexual function, digestion, and immune response. Moreover, histidine is vital in maintaining the integrity of the myelin sheath, which is the protective covering of the nerve cells.
  1. Phenylalanine: For the neurotransmitters norepinephrine, epinephrine, dopamine, and tyrosine, phenylalanine acts as a precursor. Furthermore, phenylalanine is crucial in maintaining the function and structure of enzymes as well as proteins. It also helps in the creation of the other amino acids.
  1. Valine: One of the three branched-chain amino acids is valine. Its particular role involves in the regeneration and stimulation of muscle growth. Furthermore, valine is vital in energy production.
  1. Threonine: Elastin and collagen are structural proteins that make up connective tissues and the skin. To maintain the integrity of these structural proteins, threonine is a crucial element. Moreover, this essential amino acid helps in immune function and fat metabolism.
  1. Tryptophan: The neurotransmitter, serotonin, regulates sleep, mood, and appetite. One of its precursors is that of tryptophan. Apart from its role in serotonin production, tryptophan is important in maintaining the proper balance of nitrogen in the body.
  1. Methionine: Selenium and zinc are vital minerals needed by the body. In this regard, methionine is needed to help in the absorption of the said minerals. Moreover, this amino acid is necessary for detoxification, metabolism, and tissue growth.
  1. Leucine: Another branched-chain amino acid is leucine. It is needed in muscle repair and protein synthesis. Furthermore, this amino acid helps in the production of growth hormones, wound healing, and regulation of blood glucose levels.
  1. Isoleucine: The third of the branched-chain amino acids is isoleucine. This amino acid is mostly found in the muscle tissues; as such, it is needed in muscle metabolism. Moreover, isoleucine is crucial in energy regulation, hemoglobin production, and immune function.
  1. Lysine

This amino acid is vital in the production of elastin and collagen. Furthermore, it plays a significant role in immune function, energy production, absorption of calcium, enzyme and hormone production, and protein synthesis.

Based on the detailed list above, essential amino acids make up numerous vital functions. A deficiency of any of these can affect one’s health negatively, specifically the immune system, digestive system, reproductive system, and nervous system.


Essential amino acids can be sourced from the food one eats. However, studies have shown that supplemental amino acids have a wealth of health benefits as well. These include the following.

  1. Improves Sleep and Mood. A neurotransmitter that regulates behavior, sleep, and mood is serotonin, and to produce this neurotransmitter, tryptophan is required. Studies have shown that minimal levels of serotonin are linked to sleep disturbances and a depressed mood. Thus, supplemental tryptophan helps improve sleep, boost mood, and reduce signs of depression.
  1. Enhances Workout Performance. In this regard, essential amino acids which are branched-chain help the most, namely isoleucine, valine, and leucine. It not only improves athletic performance but also stimulates muscle recovery and alleviates muscle fatigue.
  1. Inhibits Muscle Loss. Older adults who experience prolonged bed rest and illnesses are most likely to suffer from muscle loss. This is where essential amino acids are most significant since it preserves lean body mass and prevents muscle breakdown.
  2. Encourages Weight Loss. Isoleucine, valine, and leucine, which are the three branched-chain essential amino acids, are helpful in encouraging fat loss. Research has shown that supplemental amino acids help decrease the percentage of body fat better than sports drinks or whey protein.

Food Sources

As mentioned, essential amino acids must come from the food one eats because the body cannot naturally manufacture them. Foods that offer all nine of the essential amino acids are called complete proteins, and these include seafood, meat, poultry, dairy products, and eggs. Plant-based sources of the essential amino acids include buckwheat, quinoa, and soy. On the other hand, incomplete proteins, which do not contain all the required essential amino acids, include nuts and beans.

For vegetarians, since not all plant-based sources offer all nine essential amino acids, it is best to take supplemental forms of the amino acids. This is to ensure that the body is getting the appropriate levels of amino acids it requires to function effectively.

With regards to the recommended daily allowance of the essential amino acids, the list below provides a detailed look of the needed amino acids for every 2.2 pounds of body weight.

  • Valine: 24 mg
  • Tryptophan: 5 mg
  • Threonine: 20 mg
  • Phenylalanine: 33 mg
  • Methionine: 19 mg
  • Lysine: 42 mg
  • Leucine: 42 mg
  • Isoleucine: 14 mg
  • Histidine: 14 mg

Prior to taking supplemental amino acids, it is highly advised that you first talk to your primary caregiver. This is to ensure that you are taking the appropriate amount in combination with a healthy diet and active lifestyle. Moreover, it is also recommended to speak with a dietician regarding healthy food sources of the essential amino acids.

20 amino acids from the 20 amino acids

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