Potency
A measure of the amount of drug required to produce a given biological effect. A more potent drug requires a lower dose to achieve the same effect. Potency is distinct from efficacy — a highly potent drug produces its effect at low doses but the maximum achievable effect may still vary.
Technical Context
Potency is measured by the EC50 (concentration producing 50% maximum response in a functional assay) or the ED50 (dose producing 50% maximum response in vivo). A drug with an EC50 of 1 nM is 10-fold more potent than one with an EC50 of 10 nM. Potency determines the dose required — more potent drugs can achieve effects at lower doses. However, potency alone does not indicate clinical superiority; efficacy (maximum achievable response), selectivity, pharmacokinetic properties, and safety all contribute. Among GLP-1 RAs, semaglutide is more potent at the GLP-1 receptor than liraglutide, contributing to its ability to achieve clinical effects at lower molar doses.