'There's going to be a lot of unexpected babies': the side effect of GLP-1s nobody is talking about, according to a Cambridge professor | BBC Science Focus Magazine

A statin for your cholesterol. A vitamin D tablet to avoid deficiency. An antidepressant to manage your mood. A contraceptive to ward off unwanted pregnancy, or hormonal replacement therapy (HRT) to get you through the menopause.

We rely on our pills to keep us going, happy, alive. But emerging science has hinted at potential sabotage.

Early evidence suggests GLP-1 weight-loss and diabetes drugs – like Ozempic, Wegovy and Mounjaro – might weaken the efficacy of certain medications.

Right now, scientists aren’t sure exactly how. In the words of Korean scientists in 2025, these drug-to-drug interactions “remain poorly understood and require further investigation” to ensure GLP-1s can be used safely. It’s a scientific cliché: more research needed.

But, while we wait for conclusive evidence, the potential risk remains for people who rely on their pills – and who are considering GLP-1 treatments.