How much does Mounjaro cost in the UK?

At UK list prices, one Mounjaro KwikPen costs £133 for 2.5mg, £180 for 5mg, £255 for 7.5mg or 10mg, and £330 for 12.5mg or 15mg. One pen lasts 4 weeks as labelled, so a year on a maintenance dose is about £2,300 to £4,300. Those are the prices pharmacies are paid from September 2025, and what you pay privately can sit above or below them.

UK price per pen

These are list prices published by Community Pharmacy England for September 2025, when Eli Lilly raised UK prices sharply. Prices change, so jot down what you pay and the date you checked. It saves a lot of squinting at old emails later.

Why does the price jump between steps?

Each strength has its own price, and the prices rise in uneven steps. Two pairs share a price: 7.5mg and 10mg are both £255, and 12.5mg and 15mg are both £330. So the step that stings is 5mg to 7.5mg, up £75 a pen, while going from 7.5mg to 10mg costs nothing extra.

Per mg of medicine, it runs the other way. A 2.5mg pen holds 10mg of tirzepatide and works out at £13.30 a mg. A 15mg pen holds 60mg at £5.50 a mg, less than half the price. That quirk is the whole reason click charts and half-doses from a bigger pen exist.

What a year costs

One pen lasts 4 weeks, so a year is 13 pens. On the maintenance doses (5mg to 15mg) that comes to about £2,300 to £4,300. In the groups in 2026, women on 15mg quoted paying about £266 a month. I've found no sign of a UK price cut. The last big change went the other way: in September 2025 the list price of a 15mg pen went from £122 to £330. There's no generic tirzepatide in the UK, so there's no cheaper version of the same medicine.

The money trade

The biggest saving that keeps you inside the leaflet's rules is staying on a lower step for longer. Going slowly is on-label. Staying on 5mg instead of 7.5mg saves £75 a pen, about £975 a year. The trade is that a lower dose may do less for you, and how fast you climb is for you and your prescriber to settle.

Taking part of a dose from a bigger pen is the saving women talk about most. The catch is that it only saves money if the pen is used past day 30, which is longer than an opened pen was tested for. Inside the 30-day rule, part-dosing from a bigger pen usually costs a little more. How to use the KwikPen walks through the pen itself.

Comparing prices is the other legal way to pay less. Look at the total for 3 months at the strengths you're likely to need, with any consultation fee and delivery added, rather than the first-order price. Check any pharmacy on the GPhC register (Great Britain) or the PSNI register (Northern Ireland). It's also worth checking the NHS rules again. From June 2026, GP prescribing covers a BMI of 35 or more plus at least four of type 2 diabetes, high blood pressure, high cholesterol, sleep apnoea and heart disease. The BMI thresholds are 2.5 lower for people of South Asian, Chinese, Middle Eastern, Black African or African-Caribbean heritage.

Ask your prescriber "I pay for my own pens. If the dose I'm on is still working, can I stay on it longer before stepping up, and what would you look for to decide?"