Many patients are now using weight loss medications like Tirzepatide (Mounjaro) or Semaglutide (Ozempic, Wegovy, Rybelsus) — either for diabetes or privately for weight loss.
These medications work partly by slowing down how your stomach empties — which can affect how well other medicines (like the contraceptive pill or HRT tablets) are absorbed by your body.
If you take the contraceptive pill
Tirzepatide (Mounjaro)
This medicine may reduce how well the pill works. You should:
- Use a non-oral method (e.g. coil or implant) or
- Add a barrier method (like condoms) for 4 weeks after starting or increasing the dose.
- Use extra protection (like condoms) if you have vomiting or diarrhoea and follow the missed pill rules (see the patient information leaflet which comes with your pill) if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.
Semaglutide (Ozempic, Wegovy, Rybelsus) and others
These do not appear to reduce the effectiveness of the pill, but side effects like vomiting or diarrhoea can still reduce how well the pill is absorbed. So, use extra protection (like condoms) if you have vomiting or have diarrhoea and follow the missed pill rules (see the patient information leaflet which comes with your pill) if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.
If you take Hormone Replacement Therapy (HRT)
This applies if your HRT includes progesterone tablets like:
- Progesterone or Utrogestan
- Norethisterone
- Medroxyprogesterone acetate
There is some concern that weight loss medications – such as Tirzepatide (Mounjaro) and Semaglutide (Ozempic, Wegovy, Rybelsus) – may reduce how well these tablets are absorbed. This could lead to irregular bleeding and may affect the protection of your womb lining (potentially leading to an increased risk of endometrial cancer).
What are the best options?
Please contact us to talk about the best choice for you.
Options include:
- Mirena coil (IUS):
- The ideal option in most cases.
- Works for 5 years as part of HRT and is also contraceptive.
- Combined HRT patch:
- It contains both hormones (oestrogen + progestogen) and bypasses the stomach.
- Increase oral progesterone dose:
- Your GP may recommend a higher dose for 4 weeks after starting or increasing the dose of your weight loss medication.
- Using progesterone vaginally:
- This is not licensed but is commonly used. You can continue this if already prescribed.