The National Health Service (NHS) has issued an urgent notice regarding the use of weight loss injections, specifically Mounjaro (tirzepatide), for patients also taking other medications. This advisory comes as many individuals set health goals for the New Year, including weight loss objectives, and highlights potential risks associated with concurrent medication use.
As of January 2026, the use of medications like Mounjaro and Semaglutide has surged, with estimates suggesting that over half a million individuals in the UK are utilizing Mounjaro for weight management. While these drugs are primarily prescribed for managing type 2 diabetes, they are increasingly being sought after for weight loss. The NHS warns that patients using these injections should be particularly cautious if they are also taking the contraceptive pill or undergoing Hormone Replacement Therapy (HRT).
NHS Warning for Contraceptive Users
The NHS has specifically alerted patients that medications like Mounjaro may interfere with the effectiveness of oral contraceptives, including the Progesterone-Only Pill. The health authority advises those affected to consider alternative contraceptive methods, such as intrauterine devices (IUDs) or implants, or to use barrier methods, such as condoms, for four weeks after starting or adjusting the dosage of their weight loss medication.
The official notice states, “Many patients are now using weight loss medications like Tirzepatide (Mounjaro) or Semaglutide (Ozempic, Wegovy) – 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 are absorbed by your body.”
Patients are also warned to take extra precautions if they experience vomiting or diarrhoea, as these conditions can further impact the absorption of the contraceptive pill. The NHS underscores the importance of adhering to missed pill guidelines outlined in patient information leaflets.
Considerations for Hormone Replacement Therapy
Those using HRT that includes progesterone tablets, such as Utrogestan or Norethisterone, should also take note of the NHS advisory. There are concerns that Mounjaro and Semaglutide may diminish the absorption of these medications, which could lead to irregular bleeding and potentially affect the protection of the womb lining, increasing the risk of endometrial cancer.
The NHS emphasizes, “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.” Those contemplating changes to their contraception methods are encouraged to consult their healthcare provider for tailored advice.
As the NHS continues to navigate the complexities of weight loss medications and their interactions with other treatments, patients are urged to remain informed and proactive in managing their health. This advisory serves as a vital reminder of the importance of discussing all medications with healthcare professionals to avoid potential complications.
In a landscape where health goals are often set with the New Year, the implications of this notice are significant for individuals relying on these treatments. As weight management strategies evolve, so too does the need for clear communication between patients and healthcare providers regarding the safe use of medications.
