AAT Bioquest

What are the differences between essential and nonessential amino acids?

Posted June 6, 2023


Essential and nonessential amino acids are building blocks of proteins, which have several critical functions in the body. The two types of amino acids are primarily categorized based on the body’s capability to synthesize them.

Basis of differentiation

Essential amino acids

Nonessential amino acids


Are amino acids that cannot be synthesized by the human body and can only be obtained from the daily diet

Are amino acids that can be synthesized by the human body and need not be taken in through diet 

Number of Amino Acids

9 of the 20 amino acids are considered essential

11 of the 20 amino acids are considered non-essential


Can be obtained through various foods such as egg, quinoa, chicken, soy, meat and vegetable protein

Are produced within the body from other amino acids and a few other components


- Form precursor molecules for the formation of neurotransmitters in the brain

- Helps in building and repairing muscle tissues 

- Removal of toxins

-  Promotes brain function

- Integral in synthesis of RBC and WBC in the body

Probability of deficiency 

Highly probability of essential amino acid deficiency as they are acquired through food

Generally low probability of nonessential amino acid deficiency, but can still occur due to illness or starvation 

Also known as

Indispensable amino acids

Dispensable amino acids


- Histidine

- Tryptophan

- Lysine

- Phenylalanine 

- Valine

- Asparagine

- Glutamine

- Tyrosine

- Cysteine

- Alanine

Additional resources

Biochemistry, Essential Amino Acids

Amino Acid Reference Chart

Amplite® Colorimetric Aspartate Aminotransferase (AST) Assay Kit