At the starting dose both are similar, but across most doses Mounjaro tends to cost more per month than the Wegovy injection. At The Weight Clinic, Mounjaro ranges from £160 to £295 a month depending on dose, while the Wegovy injection ranges from £115 to £245 — so as you titrate upward, the gap widens.
The honest answer, though, is that "which costs more" depends entirely on the dose you are prescribed, because both medicines are priced by strength. This guide breaks down the real numbers so you can plan sensibly.
The quick cost comparison
Both Mounjaro (tirzepatide) and the Wegovy injection (semaglutide) are once-weekly injections you self-administer. Prices below are our exact monthly figures — they are not interpolated or estimated.
| Mounjaro dose | Mounjaro price/month | Wegovy dose | Wegovy price/month |
|---|---|---|---|
| 2.5mg (starter) | £160 | 0.25mg (starter) | £115 |
| 5mg | £185 | 0.5mg | £125 |
| 7.5mg | £240 | 1mg | £135 |
| 10mg | £260 | 1.7mg | £175 |
| 12.5mg | £275 | 2.4mg | £230 |
| 15mg (maximum) | £295 | 7.2mg (maximum) | £245 |
The cheapest entry point is the Wegovy injection at £115/month, versus £160/month for Mounjaro. At the maximum licensed doses, Mounjaro is £295 against £245 for Wegovy.
Note that the dose numbers do not line up one-to-one — 15mg of Mounjaro is not "equivalent" to 7.2mg of Wegovy. They are different medicines with different strengths, so compare the medicine as a whole, not milligram against milligram.
Why the prices differ
The two medicines work in different ways. Wegovy is a GLP-1 receptor agonist — it mimics a natural gut hormone that controls appetite, so you feel fuller sooner and for longer, and the stomach empties more slowly.
Mounjaro activates two gut-hormone receptors — GLP-1 and GIP — at the same time. This dual mechanism is one reason it is a different product with its own pricing.
Pricing across UK online pharmacies reflects the manufacturer supply cost, the dose strength, and the dispensing service around it. What matters for your budget is the ongoing monthly cost at your maintenance dose, not the headline starter price.
The cost you actually pay changes as you titrate
Both medicines start low and increase gradually — this "titration" reduces side effects while your body adjusts. Because price rises with dose, your monthly spend usually climbs over the first few months before settling.
Mounjaro steps up as: 2.5mg → 5 → 7.5 → 10 → 12.5 → 15mg. The Wegovy injection steps up as: 0.25mg → 0.5 → 1 → 1.7 → 2.4 → 7.2mg.
Not everyone needs the maximum dose. Many people reach a maintenance dose that works for them lower down the ladder, which keeps costs lower too. Your prescriber will guide the dose based on how you respond and tolerate the medicine — a prescription is only issued if it is clinically appropriate.
What about efficacy — is the pricier option "worth it"?
Cost is only half the picture; the trial evidence matters too. These figures come from separate trials and are not head-to-head comparisons.
In the SURMOUNT-1 trial, participants on the Mounjaro 15mg dose lost on average 22.5% of body weight over 72 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this. (Jastreboff AM, et al. N Engl J Med. 2022;387(3):205–216.)
In the STEP UP clinical trial, adults on the Wegovy 7.2mg dose lost on average 20.7% of their body weight over 72 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this. (Lancet Diabetes Endocrinol. 2025;13(11).)
Because these are different trials with different participants and timeframes, you cannot simply subtract one percentage from the other. The right choice is a clinical one, weighing cost, your health history, and how you tolerate the medicine — not price alone.
Don't forget the tablet options
If you would rather not inject, the Wegovy Tablet (oral semaglutide) is now live and in stock. It contains the same active medicine as the Wegovy injection, taken as a once-daily tablet on an empty stomach with a small sip of plain water — then wait at least 30 minutes before eating, drinking anything else, or taking other medicines. Taken with food it is far less effective.
The Wegovy Tablet ranges from £115/month (1.5mg starter) to £190/month (25mg maintenance). In the OASIS 4 trial, adults on oral semaglutide 25mg lost on average 16.6% of their body weight over 64 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this. This is a cross-trial figure, not a direct comparison with the injection.
Looking further ahead, Foundayo (orforglipron) is a once-daily pill under MHRA review and expected in the UK late 2026 or 2027. It is not yet licensed or available to buy here.
Are you eligible for either medicine?
Both Mounjaro and Wegovy are prescription-only medicines available only after a clinical consultation. You may be suitable if you are aged 18 or over and have a BMI of 30 or above, or a BMI of 27–30 with a weight-related condition such as type 2 diabetes, high blood pressure or sleep apnoea.
They are not suitable if you are pregnant, planning pregnancy or breastfeeding, have type 1 diabetes, a personal or family history of medullary thyroid cancer or MEN2, a history of pancreatitis, severe gastrointestinal disease, an active eating disorder, or severe liver or kidney impairment.
Side effects to weigh alongside cost
Both medicines share the same GLP-1 side-effect profile. Common effects (affecting more than 1 in 10 people) include nausea, diarrhoea, constipation, vomiting, decreased appetite and fatigue.
Rare but serious effects include severe allergic reaction, acute pancreatitis, severe hypoglycaemia, severe gastrointestinal disease and worsening diabetic retinopathy. If you experience side effects, you can report them via the MHRA Yellow Card scheme at https://yellowcard.mhra.gov.uk/.
How to budget realistically
- Plan for the maintenance dose, not the starter price — your monthly cost rises as you titrate up.
- Factor in the full course — weight-loss treatment is typically ongoing, not a one-off month.
- Compare like for like — check whether the price includes the medicine, dispensing and delivery.
- Use verified UK pharmacies only — avoid unlicensed or overseas sellers.
At The Weight Clinic the online consultation is free, and you only pay if a treatment is prescribed and you choose to go ahead. You can compare all options on our treatments page or the weight-loss injections overview, and start the free eligibility check at start your consultation. Learn more about our regulated pharmacy or read further guides on the blog.
This article is for information only and is not a substitute for personalised medical advice. Weight-loss medicines are prescription-only, are not suitable for everyone, and are prescribed only after a clinical consultation with a GPhC-registered prescriber. Individual results vary. Always speak to a UK-registered pharmacist or doctor before starting or changing any prescription medication.
