GLP-1 agonists and contraception

What are GLP-1 agonists?

GLP-1 agonists are a group of medications used in type 2 diabetes and weight loss. Drugs include Tirzepatide and Semaglutide but are often better known by their brand names (see below). One of the main ways they work is by delayed gastric emptying, slowing down the rate in which food leaves the stomach.

Will using a GLP-1 agonist affect my contraception?

Tirzepatide (Mounjaro) works by slowing down digestion, and this can affect the absorption of some medications including oral contraception (including the combined pill and progestogen-only-pill). The College of Sexual and Reproductive Health (CoSRH) advise to use a barrier method (e.g. condoms) in addition to a contraceptive pill for 4 weeks after starting the medication, and 4 weeks after increasing the dose or strength.

Alternatively, you could consider using a non-oral method of contraception.

There is currently no evidence to suggest that GLP-1 agonists other than Tirzepatide will reduce the contraceptive pill’s effectiveness in the same way.

Diarrhoea and vomiting are common side effects of GLP-1 agonists and can both affect the absorption of oral contraception. If you vomit within 2 hours of taking an oral contraceptive pill, it counts as a missed dose. Refer to the product literature for missed day rules.

What about non-oral methods of contraception?

There is no evidence to believe that GLP-1 agonists affect non-oral methods of contraception, and therefore no extra precautions are needed whilst taking them.

Non-oral methods of contraception include the IUD (intrauterine device or copper coil), IUS (intrauterine system or hormonal coil), contraceptive implant or contraceptive injection.

Can I take a GLP-1 during pregnancy?

GLP-1 agonists should not be used during pregnancy. If you become pregnant whilst taking one of these medications, it’s important to discuss this with a healthcare professional.

Some GLP-1 agonists have a “wash-out period”, which is the period of time it takes the drug to fully leave your system. It is important to stop the medication for this amount of time before prior to a planned pregnancy.

For Tirzepatide (Mounjaro), this is 1 month. For Semaglutide (Ozempic, Wegovy), this is 2 months. For Exenatide (Bydureon), this is 3 months.

What if I need emergency contraception?

If you have unprotected sex whilst taking a GLP-1 agonist, the absorption of oral emergency contraception may be delayed, potentially making it less effective. Advise the healthcare professional you talk to which medication you take, including GLP-1 agonists. The IUD is the most effective form of emergency contraception as it provides 99% protection, works after ovulation has occurred, and is unaffected by delayed gastric emptying.

Last updated 12/01/2026