potencies

Potency is a term used across disciplines to describe the capacity to produce an effect. In pharmacology, potency refers to the amount of a drug required to achieve a given level of response; more potent drugs need lower doses. Potency is commonly quantified from dose–response curves using measures such as EC50 or IC50. It is distinct from efficacy, which is the maximal effect a drug can achieve.

Potency is influenced by pharmacokinetic factors (absorption, distribution, metabolism, excretion) and pharmacodynamic properties (receptor affinity and intrinsic activity). Competitive antagonists can reduce apparent potency by shifting the dose–response curve to the right. Importantly, potency is not a direct measure of safety or therapeutic value; a highly potent drug may have a narrow therapeutic index.

In philosophy, potency denotes the capacity to change or be actualized. Aristotle distinguished potentiality from actuality, and later scholastic and modern thinkers treated potencies as dispositions or powers that may be realized under suitable conditions. In this sense, potency is about what a thing could become, given the right circumstances.

Other uses include broader talk of power or capability in science and everyday language. The term comes from Latin potentia and has been used to illuminate how systems transition from latent possibilities to actual outcomes.