GLP-1 Weight Loss medications and Contraception

The use of GLP-1/GIP weight management medications alongside contraception, including semaglutide (Wegovy®), liraglutide (Saxenda®) and tirzepatide (Mounjaro®).

Your contraceptive needs should always be discussed with a healthcare professional, and this information is provided to help you understand the current recommendations from the Faculty of Sexual and Reproductive Healthcare (FSRH), as set out in their official patient information leaflet: https://www.cosrh.org/Common/Uploaded%20files/documents/Patient-information-GLP-1-agonists-and-contraception.pdf 

Why GLP-1 injections may affect contraception

GLP-1 medicines work by helping appetite control and improving metabolic regulation. One of their actions is to slow stomach emptying (delayed gastric emptying).

Because of this, GLP-1 medicines can sometimes cause side effects such as:

• Nausea
• Vomiting
• Diarrhoea
• Constipation
• Reduced absorption of medicines taken by orally (in some cases)

Because they slow digestion, they may also reduce the absorption of oral medicines, including contraception, particularly when:

• GLP-1 is being started, or doses increased
• Patients experience vomiting or diarrhoea
• There is significant delayed gastric emptying

Together, these effects help reduce calorie intake and support sustainable weight loss when combined with healthy lifestyle changes.

What this means for your contraception

If you are taking an oral contraceptive pill, the effect of GLP-1 agonist depends on which specific medication you are taking. slow gastric emptying, which may alter the absorption of orally administered medicines.

Tirzeptatide (e.g. Mounjaro) works slightly differently to other GLP-1 agonists and can reduce the absorption and effectiveness of oral contraceptives. Because of this, if you are prescribed tirzepatide, you should use an additional barrier method of contraception (such as condoms) alongside your pill for four weeks after starting the medicine and four weeks after any increase in dose. Alternatively, you may wish to consider switching to a non-oral contraceptive method (e.g. coil/IUD, implant, injection, patch or vaginal ring) while using tirzepatide, as these are not affected by GLP-1 medications.

For other GLP-1 agonists including semaglutide (e.g. Ozempic, Wegovy, Rybelsus, Rxenatide, Liraglutide, Dulaglutide and Lixisenatide), there is currently no evidence that these reduce the effectiveness of oral contraception itself. However, these medicines can commonly cause nausea, vomiting and diarrhoea, which may reduce the effectiveness of the pill if it is not absorbed properly. 

What to do if you have vomiting or diarrhoea

If you experience vomiting within 3 hours of taking your pill, or if you have severe diarrhoea lasting more than 24 hours, you should follow the standard guidance for missed pills and consider using condoms or another reliable method until your symptoms resolve.

Non-oral contraceptive methods (such as the coil, implant, injection, patch or vaginal ring) are not impacted by GLP-1 medications, so no extra precautions are needed if you chose one of these options.

Switching GLP-1 medications and contraception

If you are planning to switch from one GLP-1 agonist to another, the contraception advice depends on the medication. 

If you switch to tirzepatide from any other GLP-1 agonist, you should again use a barrier method with your oral contraception for four weeks after the switch and for four weeks after any dose increase, or discuss non-oral contraception options with your clinician. 

Emergency contraception and GLP-1

Emergency contraception is not yet known to be affected by GLP-1 medications, but because vomiting and diarrhoea can compromise oral emergency pills, the copper IUD (coil) remains the most effective emergency option and is not affected by gastrointestinal symptoms.

If you require emergency contraception, please tell your healthcare provider about all medications you are taking, including GLP-1 agonists.

Pregnancy and GLP-1

GLP-1 agonists should not be used during pregnancy, and there is limited safety information for use in pregnancy or while trying to conceive. Therefore, effective contraception should be used throughout treatment, and these medicines should be stopped several weeks before a planned pregnancy to allow the drug to clear from your system.

• At least one month before conception with tirzepatide 
• At least two months before conception with semaglutide

If you have any concerns about your contraception, gastrointestinal symptoms while taking GLP-1 medication, or are planning a pregnancy, we strongly recommend that you discuss your individual situation with a healthcare professional so that your contraceptive plan can be tailored to your specific needs.

Important Safety Advice

It is important to use GLP-1 medications safely and in line with clinical guidance.

Maintaining open communication with your provider is key to ensuring safe and effective treatment.

Remember:

• Do not ignore persistent or worsening symptoms
• Do not increase or stop your medication without advice
• Ensure your GP is informed of any new or unusual symptoms

Additional support

If you are experiencing side effects or have any questions about your treatment, our clinical team is here to help.

If your symptoms are severe, worsening, or you feel they require urgent medical attention, please seek immediate advice from your GP, NHS 111, or attend your nearest A&E department if appropriate.

For all other queries:

• Book a free video consultation with one of our trained clinicians through our website. Appointments are available throughout the week, including daytime and evening sessions.
• Send us your question online using our form: https://forms.medicinemarketplace.com/251345635207050 A member of our clinical team will respond by email.
• Speak to us by phone by calling 0330 175 5747, and selecting option 3.

We are here to answer your questions and provide support throughout your treatment journey.

Written by: Uzma Dala MPharm (2238839)

Approved by: Shameela Adam MPharm (2070113)