UK WEIGHT-MANAGEMENT COMPARISON
Wegovy vs Mounjaro: what is the difference and which may suit you?
Wegovy contains semaglutide and acts on the GLP-1 receptor. Mounjaro contains tirzepatide and acts on both GIP and GLP-1 receptors. Both are prescription-only, once-weekly injections used alongside dietary change and increased physical activity.
Mounjaro produced greater average weight loss than Wegovy 2.4 mg in a direct 72-week study, but that does not make it automatically safer, more suitable or better value for every patient.
The quick comparison: Wegovy vs Mounjaro
Mounjaro may offer greater average weight reduction based on the direct SURMOUNT-5 trial, but individual results vary and the study compared tirzepatide with semaglutide 1.7 mg or 2.4 mg.
Wegovy may be preferred in some clinical situations, including where its specific UK cardiovascular risk-reduction indication is relevant.
Neither medicine has a directly equivalent dose. A milligram of Wegovy is not comparable with a milligram of Mounjaro.
| Feature | Wegovy | Mounjaro |
|---|---|---|
| Active ingredient | Semaglutide | Tirzepatide |
| Main receptor action | GLP-1 receptor agonist | GIP and GLP-1 receptor agonist |
| Injection frequency | Once weekly | Once weekly |
| Current Bute Clinic starting price | £150 for 0.25 mg | £170 for 2.5 mg |
| Current highest locally listed dose | 2.4 mg at £260 | 15 mg at £320 |
| Typical escalation | Usually every four weeks from 0.25 mg to 2.4 mg | 2.5 mg for four weeks, then 5 mg; later 2.5 mg steps if needed |
| Direct trial average at 72 weeks | 15.4% reduction in SURMOUNT-5 | 21.6% reduction in SURMOUNT-5 |
| Important distinctive point | Specific UK indication to reduce major cardiovascular events in qualifying adults with established cardiovascular disease | Specific additional contraception precautions apply around starting and dose escalation |
Wegovy vs Mounjaro: how do they work?
Wegovy: semaglutide
Semaglutide acts like the naturally occurring GLP-1 hormone. It can reduce appetite, increase fullness, influence food intake and slow stomach emptying.
The dose starts low and is increased gradually to reduce gastrointestinal side effects. Our current service lists injectable doses from 0.25 mg to 2.4 mg.
Mounjaro: tirzepatide
Tirzepatide activates both GIP and GLP-1 receptors. These pathways influence appetite, food intake and blood glucose regulation.
Treatment starts at 2.5 mg weekly and normally moves to 5 mg after four weeks. Later increases are made only when needed and tolerated.
Wegovy vs Mounjaro: which produces more weight loss?
The strongest direct comparison is SURMOUNT-5. It included 751 adults with obesity, or overweight with at least one weight-related condition, and compared maximum tolerated once-weekly tirzepatide with semaglutide for 72 weeks alongside dietary and activity support.
Average weight change was −21.6% with tirzepatide and −15.4% with semaglutide. More participants receiving tirzepatide also reached weight-loss thresholds of 10%, 15%, 20% and 25%.
These are study averages, not promises. Participants were carefully selected, monitored and supported. A person’s result can be smaller, larger or absent, and tolerability may prevent use of a higher dose.
The comparison used semaglutide 1.7 mg or 2.4 mg—not the newer 7.2 mg dose now included in UK product information. The 7.2 mg injectable option is not currently listed in the Bute Clinic service price table.
Wegovy vs Mounjaro: which has fewer side effects?
There is no reliable way to predict that one medicine will cause fewer side effects for a particular patient. Both commonly affect the digestive system, especially during dose escalation.
Both medicines can also be associated with dehydration, gallbladder problems, pancreatitis, hypoglycaemia when combined with certain diabetes medicines and aspiration risk during general anaesthesia or deep sedation. Read our weight-loss injection side-effects guide.
Wegovy vs Mounjaro: important differences for pregnancy and contraception
Neither Wegovy nor Mounjaro should be used during pregnancy. Current UK product information advises stopping Mounjaro at least one month before a planned pregnancy and Wegovy at least two months before a planned pregnancy.
For people using oral contraception, tirzepatide has an additional precaution. Because reduced contraceptive exposure cannot be excluded in people with overweight or obesity, current product information advises switching to a non-oral method or adding a barrier method for four weeks after starting Mounjaro and for four weeks after every dose increase.
Vomiting or severe diarrhoea can also reduce the reliability of oral contraception with either treatment. Follow the missed-pill or illness advice for your contraceptive and contact a clinician or pharmacist.
Wegovy vs Mounjaro: heart and cardiovascular health
Wegovy has a specific UK indication to reduce the risk of major cardiovascular events in adults with established cardiovascular disease and a BMI of at least 27 kg/m². In the SELECT trial, semaglutide 2.4 mg reduced the relative risk of cardiovascular death, non-fatal heart attack or non-fatal stroke compared with placebo.
Mounjaro has substantial evidence relating to weight, blood pressure, diabetes, obstructive sleep apnoea and obesity-related heart failure, but it does not currently have the same broad UK cardiovascular event-reduction indication stated in the Wegovy licence.
This does not mean Wegovy is automatically preferred for every person with heart disease. Cardiovascular history, diabetes treatment, kidney function, symptoms and specialist advice may all affect the decision.
Wegovy vs Mounjaro: how do prices compare?
Prices below cover the currently listed four-week medicine supply. The initial consultation is free. The two columns are deliberately separate because the doses are not equivalent.
Wegovy injection
| 0.25 mg | £150 |
| 0.5 mg | £160 |
| 1 mg | £160 |
| 1.7 mg | £205 |
| 2.4 mg | £260 |
Mounjaro injection
| 2.5 mg | £170 |
| 5 mg | £200 |
| 7.5 mg | £260 |
| 10 mg | £300 |
| 12.5 mg | £310 |
| 15 mg | £320 |
Wegovy is cheaper at the currently listed starting dose and at several stages of the local pathway. Mounjaro’s price rises more sharply at higher strengths. The cheapest option is not necessarily the best option if it is unsuitable, poorly tolerated or ineffective for that person.
Wegovy vs Mounjaro: which treatment may be considered in different situations?
Do not switch or combine them yourself
Wegovy and Mounjaro should not be taken together. There is no safe online dose-conversion rule, and the next dose depends on the medicine used, current dose, last injection date, treatment gap, side effects and clinical history.
Do not overlap injections, use leftover pens, count unofficial pen clicks or begin the other medicine at a dose chosen from a comparison chart. A prescriber must assess the switch.
Wegovy vs Mounjaro at Bute Clinic
Bute Clinic by Treherbert Pharmacy provides private, face-to-face weight-management assessments. We review your medical history, medicines, measurements, previous treatment, side effects, goals and budget before discussing suitable options.
The clinic supports patients from Treherbert, Treorchy, Cwmparc, Ton Pentre, Ystrad Rhondda, Llwynypia, Tonypandy, Porth, Rhigos, Hirwaun and Aberdare.
Book a free private consultation
Call 01443 776133
The initial consultation is free. Medicine supply is privately charged and remains subject to clinical suitability and stock.
Frequently asked questions
Is Mounjaro better than Wegovy?
Mounjaro produced greater average weight loss than Wegovy 2.4 mg in SURMOUNT-5, but “better” also depends on medical suitability, side effects, cardiovascular history, contraception, cost and individual response.
Which has fewer side effects, Wegovy or Mounjaro?
Both commonly cause digestive side effects. Neither is consistently easier for every patient. The dose, escalation speed, food intake, hydration and individual sensitivity all affect tolerability.
Is Wegovy cheaper than Mounjaro?
At Bute Clinic’s prices on 20 June 2026, Wegovy starts at £150 and Mounjaro at £170. Wegovy is also less expensive than the higher Mounjaro strengths currently listed.
Are the doses equivalent?
No. The milligram strengths cannot be matched directly because semaglutide and tirzepatide are different medicines with different dose schedules.
Can I switch from Wegovy to Mounjaro?
A switch may be possible after clinical review. The prescriber will consider your current dose, last injection, response, side effects, treatment gap and health history before choosing a safe starting plan.
Can Wegovy and Mounjaro be used together?
No. They should not be combined. Overlapping treatment can increase risk and is not a recognised weight-management regimen.
Which is better if I have heart disease?
Wegovy has a specific UK cardiovascular risk-reduction indication for qualifying adults with established cardiovascular disease. However, the most suitable treatment still requires an individual clinical review.
Related guides and official information
Treherbert Pharmacy and Bute Clinic
167 Bute Street, Treherbert, Treorchy, CF42 5PE
Telephone: 01443 776133
Article information
Written by: Jonathan James, Independent Prescribing Pharmacist, GPhC number 2066318
Clinically reviewed by: Thomas Harries, Superintendent Pharmacist, GPhC number 2210031
Pharmacy registration: Treherbert Pharmacy, GPhC premises number 1043629
Published: 20/07/2026