Coprostanone is a metabolite of cholesterol. The conversion of cholesterol into coprostanol by intestinal microorganisms has been reported to occur by means of two different pathways. One pathway involves the intermediate formation of delta4-cholelestenone and coprostanone. In the other pathway, cholesterol is transformed into coprostanol by the direct reduction of the delta5 double bond. Coprostanone concentration is used as a fecal sterol biomarker in different investigations. For example, to determine of fecal sterols following a diet with and without plant sterols, to assess if faecal steroid excretion in humans is affected by calcium supplementation and other investigations.