Physiological small molecules

Physiological small molecules represent a vast and heterogeneous group of endogenous compounds, typically with a molecular weight under 900 Daltons, that are integral to biological processes. This category includes essential substances such as amino acids, fatty acids, sugars, vitamins, minerals, and signaling molecules like hormones and neurotransmitters (NIH, 2023). Because the term encompasses thousands of distinct chemical entities with diverse biological roles, it is considered a classification category rather than a specific therapeutic target. In pharmacology, these molecules often serve as the natural ligands for receptors or substrates for enzymes; therapeutic intervention usually involves modulating the concentration of a specific molecule or targeting the proteins that interact with them (PubChem, 2024). Consequently, "Physiological small molecules" is too broad to be used as a specific target for drug discovery or structured bioactivity data. Analysts should instead focus on specific members of this class, such as adenosine or cortisol, and their respective cognate receptors or metabolic enzymes (IUPHAR/BPS, 2023).

Other names

Endogenous small moleculesMetabolitesEndogenous ligandsBioactive small moleculesLow molecular weight physiological compounds

Not applicable as this is a broad category of substances rather than a single therapeutic target.