FAQ: Weight loss injections and Contraception

GLP-1 agonists are medications such as tirzepatide and semaglutide, often known by brand names like Mounjaro, Ozempic, or Wegovy. They are prescribed for individuals with type 2 diabetes or to help with weight loss. These medicines work by slowing down the rate at which food leaves the stomach.

Yes, Mounjaro (tirzepatide) reduces the absorption of the contraceptive pill. This effect is most significant during the first four weeks of starting Mounjaro and for the first four weeks after any dose change.

If you are taking Mounjaro, you must use condoms in addition to your contraceptive pill for four weeks after you start the medication and for four weeks after any dose increase.

Yes, Mounjaro can reduce the effectiveness of any oral contraceptive, including the Progesterone-Only Pill.

GLP-1 agonists do not affect non-oral contraception methods. Therefore, it is safe to use options like the coil (IUD), implant, or injection without any extra precautions when taking a GLP-1 agonist. If you are interested in changing your contraception, you should discuss this with the surgery.

For these specific GLP-1 agonists, there is no proof that they directly make the contraceptive pill less effective. However, they commonly cause diarrhoea and vomiting, which can be significant.

Diarrhoea and vomiting can occur with GLP-1 agonists and might make the contraceptive pill less effective. If you vomit within three hours of taking your pill, or experience severe diarrhoea for more than a day, you should follow the guidance for missed pills Forgot Your Pill? Use Our Missed Pill Calculator | The Lowdown. If diarrhoea or vomiting continues, consider using a different type of contraception that is not a pill, or use condoms as an additional method.

If you are switching to Mounjaro from any other GLP-1 agonist, you should use condoms for four weeks after switching and for four weeks after any dose increase. Continue taking your contraceptive pill as well. You might also consider switching to a different type of contraception that is not a pill while using Mounjaro.

It is not yet known if GLP-1 agonists affect emergency contraception pills. The copper IUD (coil) is considered the best emergency contraception option and its effectiveness is not impacted by diarrhoea or vomiting. If you require emergency contraception, inform your healthcare provider about all medications you are taking, including GLP-1 agonists.

No, GLP-1 agonists should not be used if you are pregnant. It is crucial to use effective contraception when taking these medicines. If you become pregnant while on these medications, you should speak to your doctor immediately. You should also stop taking GLP-1 agonists several weeks before attempting to conceive.

The recommended time to stop before planning a pregnancy varies by medication:

  • Tirzepatide (Mounjaro): One month
  • Semaglutide (Ozempic, Wegovy, Rybelsus): Two months
  • Exenatide (Bydureon BCise): 12 weeks