Creatine is a key player in the phosphagen energy system, the primary source of ATP during short-term, high intensity activities.

3,5-Diiodotyrosine Dihydrate is the substrate for the assay of halogenated tyrosine and thyroid hormone aminotransferase, also the intermediate in the biosynthesis and alternative pathways of thyroid hormones metabolism.

Nepsilon-Acetyl-L-lysine is an R-chain N-acetylated α amino acid used together with other lysine analogues to differentiate and characterized various aminoacylases and regulator 2 (Sir2) enzymes/sirtuins.

5-Hydroxy-L-tryptophan is a hydroxylated metabolite of L-Tryptophan.

H-D-cis-Hyp-OH is an endogenous metabolite.

Selenomethionine is a naturally occurring amino acid containing selenium, is a common natural food source of selenium.

Triiodothyronine is a thyroid hormone generated by deiodination of the prohormone thyroxine (T4) and is a potent agonist of both thyroid hormone receptors TRα and TRβ (Kis = 2.3 nM for both).

NMDA is an amino acid derived specific agonist at the NMDA receptor.

L-pyroglutamic acid is a natural nutrient and amino acid derived from glutamic acid. It is a metabolite in the glutathione cycle that is converted to glutamate by 5-oxoprolinase.