Women taking weight loss injections must use effective contraception, according to new guidance issued on June 5 2025, by the UK’s medicines regulator, The Medicines and Healthcare products Regulatory Agency (MHRA).
Picture showing MHRA-approved Wegovy – Mounjaro
Key Takeaways
Contraception Required During Use
Women of childbearing potential must use effective contraception while taking Mounjaro or Wegovy.
These medicines must not be taken:
- During pregnancy
- While actively trying to become pregnant
- During breastfeeding
Stop Treatment If Pregnant or Breastfeeding
If you become pregnant while using either medicine, then you should stop the treatment immediately.
This is due to a lack of sufficient safety data on the use of these medications during pregnancy, and the potential for harm to the fetus is unknown.
Wait Before Trying to Conceive
In some cases, the MHRA recommends that contraception be continued for up to two months after stopping the medication before attempting pregnancy.
This ensures the drug is fully cleared from the body.
What the MHRA guidance is advising patients on Wegovy or Mounjaro
The MHRA warned that glucagon-like peptide-1 receptor agonists (GLP-1 RAs), such as Mounjaro (tirzepatide) and Wegovy (Semaglutide), should not be taken during:
- pregnancy
- while trying to conceive
- during breastfeeding
The regulator advised anyone who becomes pregnant while using these medications to stop immediately, citing insufficient safety data to determine if they could harm the baby.
In some cases, contraception should continue for up to two months after stopping the medication before attempting to conceive.
Additional Concerns
Additional concerns were raised about the effectiveness of oral contraceptives in patients taking tirzepatide-based drugs like Mounjaro. According to the MHRA, Mounjaro may reduce the effectiveness of oral contraception in individuals who are overweight.
As a precaution, patients in this category are advised to use a non-oral form of contraception alongside their current method, particularly during the first four weeks of starting Mounjaro or after any dose increases.
The guidance follows growing concerns that some individuals may not be using these medications safely, especially outside their intended purpose of managing weight-related conditions and type 2 diabetes. The agency emphasized that the guidance reinforces information already included in patient leaflets and is intended as a reminder of best practices for safe use.
Other Risks Highlighted
The MHRA also highlighted the risk of acute pancreatitis, a rare but serious side effect of GLP-1 drugs. Patients are urged to be aware of symptoms such as severe stomach pain that radiates to the back and persists. Immediate medical attention is advised if such symptoms occur.
In a strong warning against the purchase of these medicines from unregulated sources, the regulator stressed that GLP-1 medications should only be obtained from legitimate pharmacies. Buying from beauty salons or through social media poses a risk of receiving counterfeit or unsafe products.
MHRA chief safety officer Dr. Alison Cave emphasized that these medications are approved for specific medical conditions and should not be used for aesthetic or cosmetic purposes. She warned that they are not a quick fix for weight loss and have not been proven safe when used outside of their licensed indications.
Final Thoughts
The guidance is intended as a central resource for patients seeking reliable information on the safe use of GLP-1 medicines, but should not replace the patient information leaflet or consultations with healthcare professionals during the prescribing process.
The UK’s National Pharmacy Association (NPA), urged both pharmacists and patients to take note of the updated MHRA advice. They reported that community pharmacies are experiencing unprecedented demand for weight loss injections and encouraged patients with concerns to seek guidance from their pharmacist.
The MHRA’s announcement comes amid rising concern over adverse events related to these drugs.
Medical Disclaimer
NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information on this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.
The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.
