{"term":{"id":"14126","title":"efficacy","longtitle":"IUPAC Gold Book - efficacy","doi":"10.1351\/goldbook.14126","code":"14126","status":"current","definitions":[{"id":1,"text":"Extent to which a compound activates a receptor to produce a response in an assay under saturating conditions.","notes":{"1":"Usually compared to results with the positive and negative assay controls. When the compound produces a maximal signal that is \\(\\pu{100\\%}\\) of that of the positive control, it is said to be a full agonist and has high efficacy. When the effect plateaus with increasing concentration to reach an intermediary level of activity, the compound is said to be a partial agonist with lower efficacy.","2":"Due to the common overexpression of receptors in screening assays, it is not always possible to detect differences in efficacy among full agonists. A more accurate assessment of relative efficacy may require systems with lower receptor expression where it is often found that one agonist may show partial agonist character."},"contexts":[],"links":[{"term":"partial agonist","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/14174"}],"sources":["PAC, 2011, 83, 1129. 'Glossary of terms used in biomolecular screening (IUPAC Recommendations 2011)' on page 1137 (https:\/\/doi.org\/10.1351\/PAC-REC-09-05-03)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/14126\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/14126\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/14126\/plain"},"citation":"Citation: 'efficacy' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.14126","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-05-09T09:23:13+00:00"}}