Human metabolites include endogenous and exogenous metabolites; endogenous metabolites, as the name implies, are some metabolites produced and found in the human body, such as any intermediate metabolites of the citric acid cycle, which are involved in important physiological processes in the body and can serve as potential drug precursors. Exogenous metabolites including drugs, toxins and food additives are not produced and found in the organism, but originate from outside. The study of how exogenous metabolites are metabolized in the body can help accelerate drug discovery and toxicology research. In drug discovery, understanding the metabolites of a drug helps in the study of the mechanism of action of the drug.

TargetMol Human Metabolite Library collects 4454 of various endogenous and exogenous metabolites, including carboxylic acids, amino acids, biogenic amines, nucleotides, vitamins, monosaccharides, disaccharides, lipids, and carbohydrates.