Tyrosine (L-form) is a non-essential amino acid, which is primarily required for the protein synthesis. This amino acid is the precursor of dopamine, norepinephrine, and epinephrine; therefore the lower concentration of tyrosine could be a peripheral marker of the hyperdopaminergic condition hypothesized to explain psychosis. Tyrosine supplements can improve cognition, increase energy, reduce anxiety, reduce depression, reduce levels of pain.

Disodium aspartate is used in organic biosynthesis.

Alanyl-glutamine is a widely used alternative supplement to L-glutamine in the production of biopharmaceuticals. The primary advantage of using L-alanyl-glutamine in place of L-glutamine is that it reduces the level of ammonia generated during cell culture. L-alanyl glutamine also acts as an antioxidant (peroxide) and anti-apoptosis (LPS-induced) factor. Ala-Glu may be used in cell culture and insect cell culture applications. It can be used in studies on injury and sepsis, and in the effects of irradiation on leucine and protein metabolism in vivo. Alanyl-glutamine is used as dipeptide infusion solution, which is given as part of parenteral and/or enteral nutritional therapy. When the intake of nutrients or food into the mouth or directly into the gut is not possible or it is not enough to supply the body’s needs then nutrients or foods can be given intravenously or through the gastrointestinal tract or a combination of both. This is especially important for people whose bodies are under physical stress from illness or recent surgery. During illness or after surgery the body requires nutrition or food. Amino acids are the building blocks used by the body to make proteins. Dipeptiven is usually given as a supplement to amino acid solutions or an amino acid containing infusion regimen as part of complete nutritional support.

Proline (L-Proline) is one of the twenty amino acids used in living organisms as the building blocks of proteins. Proline is a non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons. Proline is used in pharmaceuticals as an excipient and as an active substance in nutritional supplements. Proline is not commonly used in pharmaceuticals as an excipient. It is approved for use in Privigen (IVIg) and Hizentra (SCIg) solution for injection as a stabiliser for IgG. Proline is also contained in low amounts in several vaccines, e.g. Havrix 720 Kinder (Hepatitis A).

L-threonine is an essential amino acid. Threonine is a precursor of glycine. The biochemical studies on rats proved that glycine is synthesized from threonine (through threonine dehydrogenase pathway). Threonine dehydrogenase is the key enzyme in mammals like pigs, cat, and rats for degradation of 80% threonine. In adult humans, degradation of 7–11% of threonine is done by threonine dehydrogenase. The human L-threonine 3-dehydrogenase gene (GeneID: 157739, UniProtKB: Q8IZJ6 (TDH_HUMAN)) is an expressed pseudogene having lost the splice acceptor site preceding exon 6 and codon arginine-214 (CGA) is mutated to a stop codon (TGA). A few trials demonstrated that oral L-threonine may alleviate clinical signs of amyotrophic lateral sclerosis and spasticity in humans. L-Threonine has recently been brought into agricultural industry for balancing the livestock feed.