Displaying 2 results of Norethisterone Stable Isotopes Norethisterone is a synthetic hormone used in birth control pills and to treat conditions such as endometriosis and menstrual disorders. Norethisterone stable isotopes refer to versions of the molecule that have a consistent number of protons and neutrons in their atomic nuclei, making them useful in research and medical applications. These isotopes can be used to study the metabolism and pharmacokinetics of norethisterone, and to develop more effective treatments for reproductive health issues.