Metabolized

Metabolized is the process by which a substance is chemically altered by a living organism, producing one or more metabolites. In biology and medicine, metabolism encompasses the transformation of xenobiotics (such as drugs and environmental chemicals) and endogenous compounds (like hormones and nutrients). Most metabolic reactions occur in the liver, though other tissues contribute.

During metabolism, enzymes catalyze reactions that increase water solubility to facilitate excretion. Phase I reactions (oxidation, reduction, hydrolysis) introduce or reveal polar groups. Phase II reactions (conjugation) attach polar groups such as glucuronide, sulfate, glycine, or methyl groups to form more water-soluble compounds. Some substances are metabolic precursors (prodrugs) that become active drugs after metabolism. Some metabolites may be pharmacologically active or toxic (bioactivation).

Excretion then eliminates metabolites mainly through the kidneys into urine or via the biliary system into feces. Oral drugs may undergo first-pass metabolism in the liver, reducing systemic exposure before reaching circulation.

Metabolism is influenced by genetics (enzyme polymorphisms), age, liver and kidney function, disease, nutrition, and drug interactions that induce or inhibit metabolic enzymes. Environmental factors, circadian rhythms, and co-ingested substances also alter rates.

Understanding whether a compound is metabolized and how quickly it is metabolized informs pharmacokinetics, dose design, safety assessments, and toxicology.