I lost half my weight on fat jabs – being skinny is great but ‘Ozempic butt’ is a real side effect

Wegovy – a modified version of type 2 diabetes drug Ozempic – and Mounjaro are the leading weight loss injections used in the UK.

Wegovy, real name semaglutide, has been used on the NHS for years while Mounjaro (tirzepatide) is a newer and more powerful addition to the market.

Mounjaro accounts for most private prescriptions for weight loss and is set to join Wegovy as an NHS staple this year.

How do they work?

The jabs work by suppressing your appetite, making you eat less so your body burns fat for energy instead and you lose weight.

They do this my mimicking a hormone called GLP-1, which signals to the brain when the stomach is full, so the drugs are officially called GLP-1 receptor agonists.

They slow down digestion and increase insulin production, lowering blood sugar, which is why they were first developed to treat type 2 diabetes in which patients' sugar levels are too high.

Can I get them?

NHS prescriptions of weight loss drugs, mainly Wegovy and an older version called Saxenda (chemical name liraglutide), are controlled through specialist weight loss clinics.

Typically a patient will have to have a body mass index (BMI) of 30 or higher, classifying them as medically obese, and also have a weight-related health condition such as high blood pressure.

GPs generally do not prescribe the drugs for weight loss.

Private prescribers offer the jabs, most commonly Mounjaro, to anyone who is obese (BMI of 30+) or overweight (BMI 25-30) with a weight-related health risk.

Private pharmacies have been rapped for handing them out too easily and video calls or face-to-face appointments are now mandatory to check a patient is being truthful about their size and health.

Are there any risks?

Yes – side effects are common but most are relatively mild.

Around half of people taking the drug experience gut issues, including sickness, bloating, acid reflux, constipation and diarrhoea.

Dr Sarah Jarvis, GP and clinical consultant at patient.info, said: “One of the more uncommon side effects is severe acute pancreatitis, which is extremely painful and happens to one in 500 people.”;

Other uncommon side effects include altered taste, kidney problems, allergic reactions, gallbladder problems and hypoglycemia.

Evidence has so far been inconclusive about whether the injections are damaging to patients' mental health.

Figures obtained by Flying Eze show that, up to January 2025, 85 patient deaths in the UK were suspected to be linked to the medicines.