GLP-1 price spread analysis: the same-pen gap

How much does the same GLP-1 pen vary in price across UK pharmacies? Our GLP-1 price spread analysis answers that with one number per medicine: the gap between the cheapest and priciest provider for an identical product. On the 25 August 2026 board that gap runs to £89 a month on Mounjaro — for a pen made by one manufacturer, to one specification, dispensed against one prescription.

The spread is the single most useful figure in this market. It tells you how much money is on the table if you shop the board rather than the first name you recognise. Below we break the spread down by medicine, by dose, and by what actually drives it.

The headline spread by medicine

Every provider dispenses the same licensed pen. The differences are commercial, not clinical. Here is the starter-dose spread across all three tracked medicines.

In percentage terms, the priciest Mounjaro starter is 68% dearer than the cheapest. The Wegovy injection spread is even steeper at 105%. Same molecule, same box, double the price.

Why the spread exists at all

A GLP-1 pen is a commodity from the buyer's point of view — you cannot get a "better" Mounjaro by paying more. So what are you paying for when you pay above the board low?

Wholesale buying power

High-volume pharmacies negotiate keener supply terms and pass some of that on. Lean online dispensers such as Next Script, Nulife and Get Weightloss sit at the bottom of every table for exactly this reason.

Service model

Full-service clinics bundle prescriber time, dose-titration support and, in some cases, coaching. That is real cost, and it explains why names like Numan (£219) and Voy (£214) sit near the top. Whether that bundle is worth £80+ a month over a lean dispenser is your call — but you should make it knowingly.

Brand premium

High-street names charge for recognition. Boots (£179) and Superdrug (£179) are not the cheapest, but plenty of people pay for a familiar shopfront and a returns desk.

Our recommended provider, The Weight Clinic, sits mid-board on sticker (£160 ongoing for Mounjaro 2.5 mg) but drops the first month to £125 with code NEWME, offers monthly video reviews, and refunds you if the prescriber declines. That combination — service plus a genuine first-order discount plus a decline refund — is the value case, not the raw starter price.

The spread widens at higher doses

Most people do not stay on the 2.5 mg starter. The dose that matters is your maintenance rung — usually 5, 10 or 15 mg. And the spread grows in cash terms as the dose climbs, because pricier providers scale up faster.

A £90-a-month gap at maintenance is over £1,000 a year. That is the number worth optimising — not the starter price you pay for four weeks. For a dose-by-dose view of who holds the low, see our cheapest GLP-1 by dose tracker and the full Mounjaro price index.

Does the cheapest provider hold across the board?

Not always. On Wegovy, the lowest price passes between several pharmacies as the dose rises. On Mounjaro this month, the lean dispensers — Next Script and Medicine Marketplace — trade the low across most rungs. That means chasing the absolute floor can involve switching pharmacies mid-titration, which resets first-order discounts and adds admin each time. Usually not worth it for a few pounds; clearly worth it if your current provider sits £60+ above the board.

First-month offers distort the spread

Several providers discount the starter dose only. Chemist4U drops Mounjaro 2.5 mg to £122 first month; Pharmacy2U to £124.99; The Weight Clinic to £125 with NEWME. These narrow the apparent spread for month one, then vanish. Always model the spread at your ongoing maintenance price, because that is what you pay for the other 11 months. We cover the traps in the hidden costs of weight-loss injections.

Price is not the same as value

The spread measures money, not outcomes. Trial evidence puts tirzepatide (Mounjaro) ahead of semaglutide (Wegovy) on average weight loss — around 21% at higher doses in SURMOUNT-1, versus roughly 15% for semaglutide in STEP 1, and about 20% vs 14% in the head-to-head SURMOUNT-5. So the cheapest sticker is not automatically the best value per kilogram. For that comparison, read Mounjaro vs Wegovy cost per percentage point. You can also sort every live figure yourself on our homepage price table.

Compliance note

Mounjaro and Wegovy are prescription-only medicines. A prescriber decides whether treatment is suitable for you — typically at a BMI of 30+, or 27+ with a weight-related condition. This article is price and information analysis only, not medical advice. Common side effects include nausea, diarrhoea and constipation; report any suspected side effect through the MHRA Yellow Card scheme. Buy only from GPhC-registered pharmacies or CQC-regulated clinics — never from unregulated sellers or "compounded" versions, which fall outside UK safety oversight.

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