On 14 August 2025, Eli Lilly announced that it would raise UK list prices for Mounjaro (tirzepatide) by up to 170%, effective from 1 September 2025. It was the single largest price change for a weight loss medication in the UK market since GLP-1 drugs became widely available. Here is what happened and what it means for private patients.
What changed and by how much
The price increase applied to all doses of Mounjaro purchased privately. At the highest end, the 15mg maintenance dose rose from £122 to £330 per month — a 170% increase. Lower doses saw smaller but still significant rises. The 5mg dose approximately doubled from around £92 to £180.
| Dose | Price before Sept 2025 | Price from Sept 2025 | Change |
|---|---|---|---|
| 2.5mg | ~£92/mo | ~£133/mo | +45% |
| 5mg | ~£92/mo | ~£180/mo | +96% |
| 7.5mg | ~£107/mo | ~£229/mo | +114% |
| 10mg | ~£107/mo | ~£249/mo | +133% |
| 12.5mg | ~£122/mo | ~£289/mo | +137% |
| 15mg | ~£122/mo | ~£330/mo | +170% |
Prices are list prices as announced. Actual prices charged by pharmacies may vary.
Why did Eli Lilly do this?
Eli Lilly gave two primary reasons. First, when Mounjaro launched in the UK, its list price was set significantly below the European average in order to facilitate timely NHS availability — essentially a deliberate introductory pricing strategy to avoid delays to NHS access negotiations. The company said the new price brings the UK into line with other developed markets.
Second, the increase came in the context of US political pressure. President Trump had publicly demanded that pharmaceutical companies raise drug prices in other countries to justify lowering them in the United States, arguing that American patients were subsidising lower prices elsewhere. While Eli Lilly was not confirmed to be part of those specific negotiations, the timing and stated rationale were consistent with this dynamic.
What happened in the market
Pharmacies absorbed some of the increase where they could. Some providers — including Voy — announced they had absorbed part of the cost rather than passing it on in full immediately. But all providers were ultimately affected by the same wholesale price change.
The increase accelerated an existing trend: many private patients began switching from Mounjaro to Wegovy. Wegovy prices were unaffected by the Lilly announcement, making it comparatively more attractive for patients whose primary consideration was cost rather than efficacy. Some pharmacies reported increased demand for Wegovy in the weeks following the announcement.
What does this mean now?
As of April 2026, Mounjaro remains significantly more expensive at higher doses than it was before September 2025. Wegovy at most doses now costs materially less per month. The launch of Wegovy 7.2mg in January 2026, which achieves comparable weight loss to Mounjaro 15mg, has made the cost-efficacy calculation more favourable for semaglutide than it was before.
For patients prioritising clinical efficacy above cost, Mounjaro at 15mg remains the highest-efficacy single-drug option at standard doses. For patients where cost is a primary factor, Wegovy now offers comparable weight loss outcomes (at 7.2mg) at a lower price point. The current prices for both drugs are in our comparison tool.