What will the new price of Mounjaro be after September’s hike?
Peter Paumgardhen, Robert Price | Last update: 24th August 2025
This is still the number one question amongst the SlimrChat community and it is causing a lot of anxiety amongst Mounjaro users. On August 18, we built estimates based on what we knew then. Since that time, new details have emerged, including confirmation of a rebate scheme, a communication to pharmacies, and several pharmacy price announcements. These updates give us a clearer picture, although it remains complicated.
Eli Lilly’s list prices are rising sharply from September. But the list price is not the price that patients actually pay. Discounts, rebates, pharmacy markups and competition still determine what you actually end up paying.
SlimrChatters have already reported new pharmacy prices across the UK, many of which were lower than we expected given the headline increases. We now understand that this is because of a new “Discount Price” rebate scheme from Lilly.
TL;DR
- Mounjaro’s UK list price is increasing by 45 to 170 per cent from 1 September.
- Eli Lilly, the company behind Mounjaro, has created a rebate scheme that lets pharmacies claim money back if they pass savings on to patients. This creates a “Discount Price” that sits below the new list price.
- Reported September prices from a number of pharmacies cluster around this Discount Price.
- SlimrChat’s updated estimate for private prescription prices ranges from about £134 to £413 per dose, depending on dose and pharmacy.
- Annual costs will increase from about £1 500 to £3 300 today to £2 600 to £4 400 from September, which is an extra £1 100 a year. That equals a rise of 74% at the low end and 34% at the high end.
- The official reason for the change is to align UK prices with Europe and reduce incentives for parallel exports.
- SlimrChat is tracking real prices and invites members to share updates, tips and experiences.
- People are transitioning from Mounjaro to Wegovy to avoid ending their weight loss journey due to the cost.
People in our community, part of the estimated one million private users in the UK, are asking the same question: what will Mounjaro cost us next month? We’re helping to put this puzzle together by sharing information, comparing notes and keeping each other informed as pharmacies update their prices.
1. What Lilly actually announced
The new list prices are the official wholesale prices. These are charged to wholesalers and form the starting point for the market. But here is the catch: this price is not the same as what you are charged for your private prescription.
That is because of two things:
- Rebates: confidential discounts or paybacks negotiated between manufacturer, wholesalers and pharmacies.
- Trade margins: pharmacies add their own markup, which varies widely.
This is why prices for the same dose of Mounjaro can differ so much across the 70 plus online pharmacies in the UK. If you have been left confused by headlines quoting “list price”, you are not alone.
What is new is that Eli Lilly has now created a rebate scheme. Pharmacies that take part can claim money back from Eli Lilly, provided they pass the savings on to patients and report their sales. This creates a new “discount price” level that sits below the official list price and explains why SlimrChatters began seeing pharmacy prices that looked far lower than the headline 170 per cent increase.
But thanks to reporting from Chemist and Druggist and confirmation in pharmacy communications, we now know there is more to it. Pharmacies that sign up to a rebate programme will be able to claim money back from Eli Lilly, provided they set their patient prices in line with a new “discount price” level and report their sales.
Current list price, new list price and discount price by dose:
This explains why community members began seeing pharmacy prices that seemed too low compared to the headline increases.
2. What we were paying before the hike
Before September, private prescription prices varied widely across the UK market. Some pharmacies were consistently among the cheapest, while others charged significantly more. For example, the 15 mg dose ranged from about £145 to £330.
Current (pre-hike) private prescription prices, low and high by dose:
3. Building an estimate for September
When we first estimated September prices, we applied Lilly’s list price increases to the cheapest available prices before the hike. That gave us a wide range.
With the new information, we now know that the rebate scheme introduces a discount price that sits below the new list price. Many pharmacies appear to be using this as the starting point from which their final patient prices are set.
Peter Paumgardhen, co-founder of SlimrChat, explains:
‘Based on the early price announcements shared by SlimrChatters and the news of Lilly’s rebate scheme, we began to see a clear pattern. The discount price, together with the markups in pounds per dose that pharmacies were already using before the increase seemed to explain the new figures coming in. On that basis we have modelled an updated prescription price range that we believe has a good chance of predicting where prices will land from 1 September. We also see that the markup percentage has been reduced. This makes sense as the operational costs for pharmacies, the work of handling prescriptions and shipping orders, do not rise simply because the list price has gone up.’
This gave us the following guesstimate ranges for new private prescription prices:
This means that our updated guesstimates now follow the discount price rather than the list price, and take into account that pharmacies appear to be adding markups in pounds per dose rather than keeping the same percentage margin as before.
4. Comparing our estimate with what pharmacies are saying
Community members have shared screenshots and updates of the new September price lists. Some pharmacies, including Chemist4U, Chequp, AYP, Livewell and Rightangled, now have prices live.
Most are clustered around the discount price levels with variations up or down depending on the pharmacy. A few providers, such as PPRX, are charging prices that are closer to the full list price. Others, such as Pillsorted, are experimenting with membership models that promise lower member prices.
Reported September prices from different pharmacies, and % increases, dose by dose:
This shows that the rebate scheme is real and is being passed on to patients by many providers.
Below follows a summary of the estimated private prescription prices (high and low), list price, discount price and the average new prescription price from reported pharmacies:
Reported prices-to-date support the SlimrChat estimate.
5. What this could mean for your annual treatment costs
We have looked again at what this all could mean for Mounjaro treatment costs over a 12-month period. The model assumes starting at 2.5 mg, then titrating up to 15 mg, and staying on 15 mg for the final 6 months.
- Using the lower end of our updated range, the annual cost rises from £1 501 today to £2 613 from September, an increase of £1 112 or 74%.
- Using the higher end of our updated range, the annual cost rises from £3 315 today to £4 427 from September, an increase of £1 112 or 34%.
This remains a rough calculation. Your actual costs will depend on your pharmacy, your dose, and whether you shop around. The bottom line is that even with the rebate scheme, annual costs rise significantly compared to before September.
6. How do we compare US prices?
One of the reasons often suggested for Lilly’s decision is the gap between UK and US prices. Reports from the United States show that patients often pay the equivalent of £700 to £900 per month for Mounjaro at higher doses. Even at the high end of our estimated range the monthly costs here will be below the US costs.
It’s clear that while the UK increase is steep it still doesn’t match the price seen in the US. If part of Lilly’s motive was to bring the UK closer to American pricing, the figures so far suggest there is still a big difference.
7. Why Lilly says prices must rise
In its communication to pharmacies, Lilly explained that UK launch prices were set lower than the European average to make sure the drug reached NHS patients quickly.
That price gap has since encouraged parallel export, where UK supply is resold abroad for profit. By raising list prices and introducing a rebate scheme, Lilly aims to close the gap, protect UK supply, and maintain patient access.
8. SlimrChat community views
At SlimrChat we see this as a fact finding mission. Prices are moving, information is patchy, and it is hard for individuals to make sense of it all on their own.
Deborah King, 59 in Northamptonshire said:
‘I really don’t know how it’s going to affect me, in terms of my physical, and mental health. Like lots of people I’m already making sacrifices to pay for the drugs and now, halfway through my treatment, what am I going to have to give up?
Some proposed rises will put it at a level where it is only affordable by the rich, and it will put even more strain on me, and other people to juggle priorities when things are already stretched. I’m extremely concerned.’
Robert Price, founder of SlimrChat, says:
‘We have a lot of worried community members, and our role is to make this process easier for them. No single person can track all the changes, but together we can build a clearer picture. This helps people make real-life decisions about their health and their money.’
9. What happens next and how the community can help
Pharmacies may adjust again as rebate terms settle. More announcements are likely in the coming days and weeks.
We will continue to track what SlimrChatters are really paying. Please help by:
- Sharing updated prices from your pharmacy in the forum.
- Telling us if you are staying, switching or stopping.
- Emailing us at [email protected] with screenshots or updates.
Together, we can bring clarity to a situation that is confusing and fast-moving and make sure our community stays informed and supported.