As well as being used in a number of different forms of hormonal contraception, norethisterone is a progestin that is also used for hormonal therapy in menopausal women and can be used to delay a period. It has also been used successfully to reduce pain in women with endometriosis. You can read more about this in our guide to the best contraception for women with endometriosis.
How does it work?
The progestogen only pill containing norethisterone works by thickening the cervical fluid which can prevent sperm from entering your uterus, and by thinning the lining of your uterus preventing a fertilised egg from implanting. When used in the combined pill alongside oestrogen they also prevent ovulation.
What is it used in?
Is it androgenic?
Yes.2 (Check out our ‘Androgens’ blog for more info on what this means).
What are the side effects?
Norethisterone’s side effects vary depending on how it is taken. When it’s taken alongside other hormones, such as in the combined pill, it’s impossible to say which side effects are due to norethisterone alone.
The following side effects have been recorded with oral use of norethisterone3:
- Menstrual cycle irregularities
- Mood changes
- Breast tenderness
- Weight change