The Mounjaro price increase and your 2.5mg starter pen: clearing up the confusion

The myth: 2.5mg is the affordable entry point that escaped the price rise

This is the misconception our prescribers field most weeks: patients assume that because 2.5mg is the lowest dose, it will be the cheapest pen to obtain, and that higher doses are where the real cost lands. In practice, Eli Lilly's September 2025 list-price revision applied across all strengths. The 2.5mg pen is not a budget introduction to the medicine; it is a tolerability dose. Its purpose is to let your system adjust before your prescriber moves you to a dose with meaningful therapeutic weight-loss effect, typically at 5mg and above.

So starting at 2.5mg doesn't insulate you from the broader price shift. If you're planning the cost of treatment over several months, the figure to budget is what your provider charges per pen at each strength, because you will move through the titration schedule over time. Our overview of the September 2025 price increase has the wider context for anyone tracking what happened and why.

The practical upshot: don't choose a provider based on their 2.5mg price alone. That's roughly the worst possible signal of what ongoing treatment will cost, because the 2.5mg phase typically lasts just four weeks before your prescriber considers moving you to 5mg, a transition you can read about in more detail on our page covering the 5mg price increase specifically.

What the post-increase price actually includes, and what some providers quietly exclude

Since September 2025, typical private prices for Mounjaro have ranged roughly £149–£375 per month by dose and provider, as we've outlined on our pricing page. What varies more than people expect is what that figure actually covers.

Some providers quote a headline price for the medicine and then list consultation fees, prescription charges or delivery costs separately. A £149 figure with a £30 consultation fee and £9.99 delivery is a different proposition from a £149 figure that includes all three. The arithmetic is obvious once you do it, but plenty of people don't until they reach checkout.

At nume, one price covers the consultation, the prescription, the medicine and free next-working-day tracked delivery. We're not the cheapest option in the market, that's a deliberate decision, not an oversight. What that choice buys is a clinical infrastructure that a very low price rarely sustains: same-day prescriber review, photo-ID and live video weight verification, GP notification in line with GPhC guidance and clinical re-review before every repeat.

For a full breakdown of what changed in September and which doses were affected most sharply, the detail is on our cost-increase page.

Why 'cheapest per pen' is the wrong question to ask for a prescription medicine

It's reasonable to shop around for the best value. For a prescription medicine sourced online, though, the price is the last number that should drive the decision.

The MHRA has documented multiple enforcement actions against counterfeit weight-loss pens sold online, including an October 2025 raid on a UK manufacturing site producing fake tirzepatide pens. Earlier seizures found counterfeit pens containing insulin instead of the labelled medicine. The MHRA's Yellow Card scheme accepts reports of suspect sellers, and the regulator advises checking that any online pharmacy appears on the GPhC register, verifiable at GPhC registration number 9012878 for nume. The pattern with counterfeit sellers is consistent: prices well below market, sellers operating through social media, and no clinical assessment before supply. If you've seen a supplier claiming Mounjaro in the UK with no price increase, that's precisely the kind of claim worth treating as a red flag rather than a deal.

Price is also the wrong test because the clinical process around the medicine matters as much as the molecule. Mounjaro's titration schedule, the monitoring for side effects, the contraception advice for women starting treatment, none of that is optional, and none of it is free to run properly. The reasons behind the price increase are worth reading for anyone who wants the fuller picture on what's driven UK private costs upward.

If you're weighing whether private treatment is right for you, our weight-loss treatment overview covers both the private and NHS routes honestly, including current NHS eligibility thresholds and what the phased rollout means for waiting times.