The Mounjaro price per pen is the number that actually matters when you budget for treatment — because one pen is one month, and the price changes every time your dose goes up. This guide breaks down what a single pen costs at each UK dose, why it climbs, and how to tell a genuinely cheap pen from a headline that only looks cheap.
All figures come from our live UK price table and were last checked on 4 July 2026. Always confirm the current price on the provider's own site before you order.
One Mounjaro pen = four weekly doses ≈ a 28-day supply. Across UK providers a 2.5 mg starter pen runs from about £146 to £229, and a 15 mg pen from about £289 to £359. You do not pay one flat price — you pay per pen, and the per-pen price rises as your dose steps up.
What "per pen" actually means
Mounjaro comes as a pre-filled KwikPen. Each pen holds four once-weekly doses, so one pen covers roughly 28 days. That is why UK pharmacies quote the price per pen and per four weeks interchangeably — they mean the same thing.
It also means your "monthly cost" and your "per pen cost" are the same figure. If a provider lists the 5 mg pen at £185, that is £185 every four weeks for as long as you stay on 5 mg.
Mounjaro price per pen at every dose
Mounjaro has six strengths. The table below shows the cheapest and highest per-pen prices listed across the 24 UK providers we track, alongside The Weight Clinic — our recommended pharmacy — so you can see the real spread at each dose.
| Dose (per pen) | Where it fits | Cheapest listed | The Weight Clinic | Highest listed |
|---|---|---|---|---|
| 2.5 mg | Starter — weeks 1–4, everyone begins here | £145.99 | £160 £125 first order | £229 |
| 5 mg | First maintenance dose | £173.99 | £185 | £259 |
| 7.5 mg | Step-up dose | £222.99 | £240 | £299 |
| 10 mg | Common maintenance dose | £249.99 | £260 | £324 |
| 12.5 mg | Step-up dose | £269.99 | £275 | £344 |
| 15 mg | Maximum maintenance dose | £288.99 | £295 | £359 |
Cheapest and highest listed prices are the base (ongoing) per-pen prices across 24 UK providers. Prices last checked 4 July 2026 — confirm on the provider's site before ordering.
Two things stand out. First, the gap between the cheapest and dearest pen at the same dose is wide — over £80 at 2.5 mg and around £70 at 15 mg. Same medicine, same pen, very different price. Second, The Weight Clinic sits close to the cheapest end at every dose while including needles and monthly video reviews.
Why the price climbs as you go up
Nobody stays on the 2.5 mg starter pen. It is a four-week introduction dose designed to ease side effects, not a treatment dose. From there you step up — 5 mg, then 7.5, 10, 12.5 and, for some people, 15 mg — spending at least four weeks at each level.
Higher-strength pens hold more tirzepatide, cost the pharmacy more, and are priced accordingly. So your monthly bill is not fixed: it rises as your dose rises, then levels off once your prescriber settles you on a maintenance dose (usually 5, 10 or 15 mg).
A realistic way to budget is to look at the pen price for the maintenance dose you are likely to land on, not the starter price. If you expect to sit at 10 mg, budget around £250–£325 a pen depending on provider — not the £146 starter figure.
Our pick for a clear per-pen price
The Weight Clinic — our recommended provider — shows one honest price per pen with needles and monthly video reviews included. The consultation is free to begin and you're refunded if you're declined. Code NEWME takes £35 off your first order (2.5 mg starter pen from £160 to £125).
See The Weight Clinic → Compare where to buy firstCheapest pen vs best value: read the price properly
The lowest headline number is not always the cheapest pen once you actually order. Three things distort a per-pen price:
- First-month promos. Some pens have a discounted intro price on your first order only. The Weight Clinic's 2.5 mg pen, for example, is £125 for a first order but £160 ongoing. Compare the ongoing price, not the promo, if you plan to continue.
- What's included. A low pen price that then charges for delivery, needles or the consultation can end up dearer than a slightly higher all-in price. Check whether cold-chain delivery and pen needles are in the number.
- Dose you'll settle on. A provider that is cheapest at 2.5 mg is not automatically cheapest at 10 mg. Match the comparison to your likely maintenance dose.
Over a full year on a 5 mg maintenance dose you'd buy about 13 pens. At The Weight Clinic's £185 that's roughly £2,405 a year; at the cheapest listed £173.99 it's about £2,262 — a real difference, but small enough that included needles, refund-if-declined and monthly reviews can tip the value the other way.
How the per-pen price fits your first order
Your first pen will almost always be the 2.5 mg starter, so that is the figure to focus on when you begin. From your second month the price steps up with your dose. If you want the full ordering walkthrough, see how to start Mounjaro in the UK, and check you meet the criteria in our Mounjaro eligibility guide before you pay for anything.
One more variable worth knowing: price only matters if the pen is in stock. Higher doses can be harder to source during shortages — our stock and availability guide covers what to do if your dose is unavailable.
FAQ: Mounjaro price per pen
How many doses are in one Mounjaro pen?
One Mounjaro KwikPen holds four once-weekly doses — roughly a 28-day supply. That is why prices are quoted per pen and per four weeks: one pen is one month of treatment.
Why does the price per pen go up as the dose increases?
Higher-strength pens contain more tirzepatide, so they cost the pharmacy more and are priced higher. Across UK providers a 15 mg pen typically costs around double a 2.5 mg starter pen.
Is the cheapest pen always the best value?
Not always. A low first-month promo can sit above a higher ongoing price, and some low headline prices exclude delivery, needles or the consultation. Compare the ongoing per-pen price plus what's included, not just the intro offer.
Do I pay the same price every month on Mounjaro?
No. You start on the 2.5 mg pen, then step up through 5, 7.5, 10, 12.5 and possibly 15 mg. Each step is a different, usually higher, per-pen price, so your monthly cost rises until you settle on a maintenance dose.
What does one Mounjaro pen cost at The Weight Clinic?
The 2.5 mg starter pen is £160, dropping to £125 for a first order with code NEWME. The 5 mg pen is £185, rising to £295 for the 15 mg pen. Prices last checked 4 July 2026.
The bottom line
Think in pens, not vague "monthly" figures: one pen is one month, and the per-pen price rises as your dose steps up from the 2.5 mg starter to your maintenance dose. Compare the ongoing price at the dose you'll actually settle on, check what's bundled in, and start from a regulated pharmacy. You can see every provider ranked by price on our homepage comparison table.
Ready to see your real per-pen price?
The Weight Clinic is our recommended provider: one clear price per pen, needles and monthly video reviews included, free consultation to begin, and a refund if you're declined. Use code NEWME for £35 off your first order.
Start with The Weight Clinic → Back to the price table