Mounjaro.

Mounjaro is the brand name for tirzepatide, a once-weekly prescription injection made by Eli Lilly. It is licensed in the UK for weight management in adults alongside a reduced-calorie diet and increased physical activity, and separately for type 2 diabetes. It comes as a KwikPen containing four weekly doses.

In the SURMOUNT-1 trial, adults taking the 15mg dose as prescribed lost an average of 22.5% of their body weight over 72 weeks, and 21.4% on 10mg. For someone weighing 100kg that is around 22kg, though results vary from person to person and depend on diet and activity. Your prescriber will discuss realistic goals with you.

Tirzepatide mimics two hormones your gut releases after eating, GIP and GLP-1. Together they tell your brain you are full, slow the emptying of your stomach and quieten the constant food noise that makes eating less so difficult. Because it lasts in the body for around a week, one injection keeps a steady effect on appetite.

Many people notice a smaller appetite within the first week or two. Weight loss builds gradually as the dose steps up, and the trial figures above are measured over 72 weeks. Your prescriber reviews your progress before every dose change.

It can. Mounjaro slows stomach emptying, which may reduce how well oral contraceptives are absorbed. Use a barrier method as well for four weeks after starting and for four weeks after each dose increase, or speak to your prescriber about alternatives.

Once a week, on the same day each week, into the abdomen, thigh or the back of the upper arm, using a very fine needle. Rotate the site each week. Full instructions come with your first order, and the clinical team can talk you through it on WhatsApp.

Keep the pen in the fridge at 2 to 8°C, in its box to protect it from light. It can be kept out of the fridge for up to 30 days below 30°C. Do not freeze it, and do not use a pen that has been frozen.

If it is within four days (96 hours) of the missed dose, take it as soon as you remember and carry on with your usual day. If more than four days have passed, skip it and take the next dose on your usual day. Never take two doses within three days of each other.

It is a licensed medicine, safe for most eligible adults under clinical supervision. The most common side effects are nausea, diarrhoea, constipation and indigestion, usually mild and easing over time. Rarer but serious risks include pancreatitis and gallbladder problems, so seek help quickly for severe or persistent stomach pain. Your medical history is always reviewed before treatment begins.

Some regain is common after stopping any weight-loss medicine, because appetite returns. The habits built during treatment make a real difference, and your prescriber can plan a gradual step-down with you rather than stopping abruptly.

Yes. If you are already on a weight-loss medicine, tell us your current medicine and dose during the consultation and upload a photo of your prescription or packaging. Where it is clinically appropriate, your prescriber can start you on an equivalent dose rather than at 2.5mg.