Ozempic vs Wegovy vs Mounjaro: What’s the Difference?
A plain-English UK guide explaining how Ozempic, Wegovy and Mounjaro differ, which are licensed for weight loss, what results the evidence shows, and which option may suit your situation.
These three names are related, but they are not interchangeable
These three names come up in almost every conversation about weight loss injections — in the news, on social media, and at the GP surgery. Most people know they are related but cannot quite explain how.
Many assume Ozempic, Wegovy and Mounjaro are interchangeable. They are not, and the differences between them matter significantly for whether you can get the drug, what it will do, what it will cost, and whether you can access it on the NHS.
This guide cuts through the confusion. It explains what each drug actually is, what makes them different, what the evidence says about weight loss results, and which one you should be asking about if your goal is to lose weight.
Most important point: Ozempic is not licensed for weight loss in the UK. It is a diabetes medication. If your goal is weight loss, the licensed options to ask about are Wegovy and Mounjaro.
Quick visual summary
A simple infographic summary to help readers understand the main points before reading the full comparison.
Why people confuse these three drugs
All three drugs belong to the same broad medication family. They all affect appetite and blood sugar, but they are not the same medicine.
Ozempic
Ozempic is semaglutide at lower diabetes doses, licensed for type 2 diabetes only in the UK. It can produce weight loss, but it is not the licensed weight loss version.
Wegovy
Wegovy is also semaglutide, but at higher weight-management doses. It is licensed for weight management and is the correct semaglutide option for obesity treatment.
Mounjaro
Mounjaro contains tirzepatide, a different drug entirely. It targets both GLP-1 and GIP receptors and is licensed for both type 2 diabetes and weight management.
Ozempic vs Wegovy vs Mounjaro — the complete comparison
| Feature | Ozempic | Wegovy | Mounjaro |
|---|---|---|---|
| Active ingredient | Semaglutide | Semaglutide | Tirzepatide |
| Manufacturer | Novo Nordisk | Novo Nordisk | Eli Lilly |
| Drug class | GLP-1 receptor agonist | GLP-1 receptor agonist | Dual GLP-1 + GIP agonist |
| Licensed in UK for weight loss? | No — diabetes only | Yes — NICE TA875 | Yes — NICE TA1026 |
| Licensed in UK for type 2 diabetes? | Yes | No | Yes |
| Dose range | 0.5mg to 2mg | 0.25mg to 2.4mg, up to 7.2mg | 2.5mg to 15mg |
| Average weight loss, trials | ~9 to 14%, at diabetes doses | ~13.7 to 20.7%, dose dependent | ~20.2 to 22.5%, dose dependent |
| NHS for weight loss? | No | Yes — specialist services, max 2 years | Yes — specialist services plus some GPs |
| Private monthly cost, May 2026 | ~£99 to £250, off-label, varies | ~£99 to £309 | ~£149 to £375 |
| Injection frequency | Once weekly | Once weekly | Once weekly |
| Oral option | Rybelsus, for type 2 diabetes only | Under MHRA review | None planned |
What each medication is actually for
Ozempic — the famous one that is not for weight loss
Ozempic contains semaglutide at doses up to 2mg weekly. It was approved in the UK in 2019 as a treatment for type 2 diabetes, where it reduces blood sugar levels and HbA1c.
The critical point is that Ozempic is not licensed for weight loss in the UK. NHS guidance states it should only be prescribed for type 2 diabetes to protect supply for patients who need it.
- Suitable for people with type 2 diabetes who meet the clinical criteria.
- Not the correct option for people without type 2 diabetes who want weight loss treatment.
- If prescribed for weight loss privately, it is being used off-label.
Wegovy — the licensed weight loss version of semaglutide
Wegovy is semaglutide at higher doses specifically developed and licensed for obesity management. The dose escalation schedule runs from 0.25mg to the standard maintenance dose of 2.4mg over 20 weeks.
The STEP 1 trial found an average of 14.9% weight loss over 68 weeks at 2.4mg. The newer 7.2mg dose produced 20.7% average weight loss over 72 weeks.
Wegovy also has cardiovascular outcome evidence from the SELECT trial, which demonstrated a 20% reduction in major adverse cardiovascular events in people with obesity and established cardiovascular disease.
Mounjaro — the most potent licensed option
Mounjaro contains tirzepatide, a different molecule from semaglutide. It activates both GLP-1 and GIP receptors, which can produce greater appetite suppression and more weight loss.
The SURMOUNT-1 trial found 22.5% average weight loss at the maximum 15mg dose over 72 weeks. The SURMOUNT-5 head-to-head trial confirmed 20.2% versus 13.7% for Wegovy 2.4mg.
Mounjaro received NICE approval for weight management in December 2024 and began NHS prescribing from March 2025 through specialist services and some GP surgeries for highest-need patients.
Similar names, different licences, doses and treatment goals
Ozempic, Wegovy and Mounjaro are often discussed together, but the right option depends on whether the goal is diabetes care, weight management, cost or clinical suitability.
Weight loss results — what the evidence shows
The most important clinical question is simple: which produces the most weight loss?
| Measure | Ozempic | Wegovy | Mounjaro |
|---|---|---|---|
| Standard dose weight loss | ~9 to 14%, diabetes doses | ~14.9%, 2.4mg STEP 1 | ~20.2%, 15mg SURMOUNT-5 |
| Maximum licensed dose weight loss | ~14% at 2mg, diabetes use | ~20.7% at 7.2mg, STEP UP | ~22.5% at 15mg, SURMOUNT-1 |
| Patients achieving 20%+ weight loss | Limited data at obesity doses | 33.2% at 7.2mg, 19% at 2.4mg | 45% at 15mg |
| Head-to-head comparison | Not compared directly at obesity doses | 13.7% vs Mounjaro’s 20.2% | 20.2% vs Wegovy’s 13.7% |
The ranking is clear: Mounjaro produces the most weight loss at standard licensed doses, Wegovy’s new 7.2mg largely closes the gap at maximum doses, and Ozempic at its licensed diabetes doses produces less weight loss than either weight-management-specific drug.
Which drug should you actually choose?
If you want to lose weight and do not have type 2 diabetes
Ozempic is not the right drug for you. The drug for you is either Wegovy or Mounjaro. Both are licensed for weight management, available privately, and available on the NHS with waiting lists.
- Maximum weight loss potential: Mounjaro leads at standard doses.
- Cost: Wegovy is now cheaper at most dose levels.
- NHS time limit: Wegovy has a 2-year NHS cap, while Mounjaro does not.
- Cardiovascular evidence: Wegovy has stronger established cardiovascular risk reduction data.
- Contraceptive pill users: Mounjaro requires extra contraception precautions.
If you have type 2 diabetes
All three drugs may be relevant, but in different ways. Ozempic is licensed for type 2 diabetes and has extensive diabetes trial data. Mounjaro is also licensed for type 2 diabetes and produces strong HbA1c reduction and weight loss.
Wegovy is not licensed for type 2 diabetes. Your GP or diabetes team is best placed to advise based on your current medications and glycaemic control.
If you have established cardiovascular disease
Wegovy has the strongest case. The SELECT trial demonstrated a 20% reduction in major cardiovascular events with semaglutide 2.4mg in people with obesity and established cardiovascular disease.
If cost is the primary concern
Wegovy is now the better value private option at most dose levels. For NHS access, Mounjaro has a slightly more accessible route for highest-need patients via GP prescribing, but neither is easily accessible on the NHS for most eligible patients.
The decision in plain terms
Ask about Wegovy or Mounjaro
If you are searching for weight loss help, ask about Wegovy or Mounjaro, not Ozempic.
For strongest standard-dose weight loss
Mounjaro currently leads at standard doses.
For affordability
Wegovy is generally the more affordable private option after Mounjaro’s 2025 price increase.
For cardiovascular evidence
Wegovy has stronger established evidence for cardiovascular risk reduction in obesity.
For type 2 diabetes
Discuss Ozempic, Wegovy and Mounjaro with your GP or diabetes team, because the best option depends on your clinical needs.
For no NHS 2-year cap
Mounjaro has an advantage because Wegovy has a two-year NHS treatment limit.
Side effects — how do the three compare?
All three drugs share broadly similar gastrointestinal side effects because all activate GLP-1 receptors in the gut.
| Side effect | Ozempic | Wegovy | Mounjaro |
|---|---|---|---|
| Nausea | ~15 to 18% | Up to 44%, higher doses | Up to 22% |
| Diarrhoea | ~8 to 10% | ~30% | ~17% |
| Discontinuation rate | ~3 to 5% | ~6.8%, STEP trials | ~6.2%, SURMOUNT-5 |
| Oral contraceptive warning | No | No | Yes — MHRA June 2025 |
| Pancreatitis warning | Yes — all GLP-1s | Yes — all GLP-1s | Yes — all GLP-1s |
| Anaesthesia warning | Yes — all GLP-1s | Yes — all GLP-1s | Yes — all GLP-1s |
The most common side effects across all three are nausea, diarrhoea, constipation, vomiting and abdominal discomfort. One meaningful difference is that Mounjaro carries a warning about reducing the effectiveness of the oral contraceptive pill during initiation and dose increases.
NHS access — a clear hierarchy
Ozempic on the NHS
Available for type 2 diabetes only, via GP prescription, when it meets NICE criteria for glycaemic control. It is not available for weight loss on the NHS.
Wegovy on the NHS
Available for weight management through specialist weight management services only. It usually requires BMI 35+ with at least one weight-related comorbidity, has a maximum two-year treatment limit and waiting times often reach 12 to 24 months.
Mounjaro on the NHS
Available for weight management through specialist services and, from June 2025, some GP surgeries for Cohort 1 patients with BMI 40+ and four comorbidities. There is no stated two-year limit.
The honest summary: if you want weight loss treatment on the NHS, you are looking at a long wait for either Wegovy or Mounjaro through specialist services. For most people in 2026, private prescription is the realistic near-term option. Ozempic for weight loss is not an NHS option at all.
Frequently asked questions
What is the difference between Ozempic and Wegovy?
Both contain the same active ingredient, semaglutide, made by Novo Nordisk. Ozempic is licensed for type 2 diabetes only, while Wegovy is licensed for weight management. Ozempic’s maximum dose is 2mg, while Wegovy’s is 2.4mg, or 7.2mg in the newer higher-dose formulation.
Can I get Ozempic for weight loss on the NHS or privately?
On the NHS, no. Ozempic should only be prescribed for type 2 diabetes. Privately, some clinics offer Ozempic off-label for weight loss, but the appropriate licensed weight loss version of semaglutide is Wegovy.
Is Mounjaro stronger than Ozempic and Wegovy?
For weight loss, yes at standard licensed doses. Mounjaro produced 20.2% average weight loss versus 13.7% for Wegovy 2.4mg in the SURMOUNT-5 head-to-head trial. Wegovy’s newer 7.2mg dose largely closes the gap at maximum doses.
Why is everyone talking about Ozempic if it is not for weight loss?
Ozempic became culturally famous before Wegovy was widely available in the UK. The name stuck as shorthand for the category, even though Wegovy and Mounjaro are the licensed weight loss options.
Which is cheaper — Ozempic, Wegovy or Mounjaro?
Ozempic is often cheapest privately, but it is not licensed for weight loss. Between the two licensed weight loss drugs, Wegovy is now generally cheaper than Mounjaro following Eli Lilly’s September 2025 UK price increase.
I have been told I am not eligible for Wegovy — could I get Mounjaro instead?
The NHS eligibility criteria and rollout routes differ between the two drugs. It is worth asking your GP specifically about Mounjaro as a separate pathway, particularly after GP prescribing of tirzepatide began for some highest-need patients.
Do Ozempic, Wegovy and Mounjaro all cause the same side effects?
Broadly, yes. The most common side effects across all three are nausea, diarrhoea, constipation and vomiting. One meaningful difference is that Mounjaro carries a warning about reducing the effectiveness of the oral contraceptive pill during initiation and dose increases.
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This article is for informational purposes only and does not constitute medical advice. Licensing, pricing and NHS availability information is correct as of May 2026 and subject to change.
Always consult a qualified healthcare professional before starting any medication. CompareTheShot is an independent comparison service — some links on this site may be affiliate links.
Medically reviewed: May 2026. Next review due: November 2026.