Short answer: Mounjaro (tirzepatide) and Ozempic (semaglutide) are different medicines, from different makers, with different UK licences. Mounjaro, made by Eli Lilly, acts on two gut hormone receptors, GIP and GLP-1, and its UK product information (SmPC, section 4.1) licenses it for type 2 diabetes and for weight management in adults with a BMI of 30 or above, or 27 or above with a weight-related condition. Ozempic, made by Novo Nordisk, acts on GLP-1 only and is licensed for type 2 diabetes, not for weight loss; the semaglutide licensed for weight management is Wegovy, and we do not supply Ozempic. In SURPASS-2 (New England Journal of Medicine, 2021), a head-to-head trial in 1,879 adults with type 2 diabetes, HbA1c fell by 2.01 to 2.30 percentage points on tirzepatide 5mg to 15mg over 40 weeks, against 1.86 on semaglutide 1mg, counting everyone who started treatment. Individual results vary.
This guide sets out what the UK product information, the MHRA and the NHS say, as of October 2026: how the two medicines differ, what the head-to-head trial found and who it was in, how their doses and side effects compare, and what to do if you want to switch from Ozempic to Mounjaro.
Is Mounjaro the same as Ozempic?
No. Mounjaro and Ozempic contain different medicines, made by different companies. Both belong to the family often called GLP-1 medicines, which work like hormones your gut releases after you eat, and both are injected once a week. Ozempic's semaglutide acts on the GLP-1 receptor alone, while Mounjaro's tirzepatide acts on the GLP-1 receptor and a second one, GIP. As the MHRA puts it, some newer medicines, like Mounjaro, also act on a second hormone involved in appetite and blood sugar control.
Ozempic is easily confused with Wegovy, because they contain the same medicine, semaglutide, from the same maker. They are licensed for different things, which is covered in our guide to Wegovy vs Ozempic. How tirzepatide works in the body is in how Mounjaro works, and the family as a whole is explained in what a GLP-1 medication is.
What is the difference between Mounjaro and Ozempic?
The main difference is the licence: Mounjaro is licensed for both type 2 diabetes and weight management, while Ozempic is licensed for type 2 diabetes only. This table sets out the rest, from each medicine's UK product information, as of October 2026.
| Question | Mounjaro (tirzepatide) | Ozempic (semaglutide) |
|---|---|---|
| Who makes it? | Eli Lilly | Novo Nordisk |
| How does it work? | Acts on two gut hormone receptors, GIP and GLP-1 | Acts on one, the GLP-1 receptor |
| What is it licensed for in the UK? | Type 2 diabetes in adults and in children aged 10 and over, and weight management in adults with a BMI of 30 or above, or 27 or above with a weight-related condition | Type 2 diabetes in adults. Not licensed for weight loss |
| What doses are there? | 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg. It starts at 2.5mg, and 15mg is the maximum | 0.25mg, 0.5mg, 1mg and 2mg. It starts at 0.25mg, and doses above 2mg are not recommended |
| What kind of pen is it? | The KwikPen: one strength per pen, 4 weekly doses in each. Needles are not in the pack, so we send them with every order | A pre-filled pen, one strength per pen; the 2mg pen holds 4 weekly doses. Needles come in the pack |
| How often is it taken? | Once a week, at any time of day, with or without food | Once a week, at any time of day, with or without food |
| Does Solira supply it? | Yes, for weight management in adults, after a GPhC-registered pharmacist reviews your consultation | No |
Both slow how quickly your stomach empties (section 4.5 of each product information), which is why both can change how some tablets taken by mouth are absorbed. Mounjaro is licensed for type 2 diabetes and weight management, and we supply it only for weight management.
Can you use Ozempic for weight loss in the UK?
No, not within its licence. In the UK, Ozempic is licensed for adults whose type 2 diabetes is not controlled well enough, alongside diet and exercise. The MHRA's own table of GLP-1 medicines lists Ozempic as licensed for diabetes and not for weight management, and the MHRA says it has not assessed the safety and effectiveness of these medicines when they are used outside their licence. It also says GLP-1 medicines should not be used to lose weight for aesthetic or cosmetic reasons.
The semaglutide licensed for weight management is Wegovy, at weekly doses up to 2.4mg, or 7.2mg for adults with a BMI of 30 or above. Mounjaro is licensed for weight management too. We do not supply Ozempic, for weight loss or for diabetes.
Who Mounjaro may suit
Treatment may be suitable if you're aged 18–85 and have a BMI of 30 or above, or a BMI of 27–29.9 alongside one of the following: high blood pressure, raised cholesterol or blood fats, obstructive sleep apnoea, cardiovascular disease, prediabetes, or type 2 diabetes.
Not sure of your BMI? Use our BMI calculator.
Is Mounjaro better than Ozempic?
Neither is better for everyone: Mounjaro and Ozempic are licensed for different things, and the right medicine depends on why you need it, your health and the other medicines you take, which is why a prescriber makes the choice with you.
SURPASS-2 (New England Journal of Medicine, 2021) compared tirzepatide, the medicine in Mounjaro, directly with semaglutide 1mg, an Ozempic dose. It was in 1,879 adults with type 2 diabetes that was not controlled well enough on metformin, who took tirzepatide 5mg, 10mg or 15mg, or semaglutide 1mg, once a week for 40 weeks. Its main measure was HbA1c, a blood test that reflects your blood sugar over the last 2 or 3 months. Counting everyone who started treatment, including people who stopped it or had another diabetes medicine added, HbA1c fell by an average of 2.01, 2.24 and 2.30 percentage points on tirzepatide 5mg, 10mg and 15mg, against 1.86 on semaglutide 1mg. Weight fell by an average of 7.6kg, 9.3kg and 11.2kg on the three tirzepatide doses, against 5.7kg on semaglutide. Individual results vary.
Three things about that trial matter when you read those figures:
- It was in people with type 2 diabetes, so it does not tell you directly how the two compare for weight management in people without diabetes.
- It used semaglutide 1mg. Ozempic's licence goes up to 2mg, and that dose was not part of the trial.
- It was open label, so people knew whether they were on tirzepatide or semaglutide, and it was funded by Eli Lilly, the maker of Mounjaro.
For weight management, the head-to-head trial is SURMOUNT-5 (New England Journal of Medicine, 2025), which compared tirzepatide with semaglutide at Wegovy's doses (1.7mg or 2.4mg), not Ozempic's, in 751 adults with obesity and without type 2 diabetes over 72 weeks. What it found is in our guide to Mounjaro vs Wegovy. If you have type 2 diabetes, our guide to Mounjaro and type 2 diabetes explains how it fits with other diabetes medicines.
Is Mounjaro safer than Ozempic?
Neither is safer for everyone. They belong to the same family of medicines, and their UK product information lists the same kinds of side effects, most often stomach and bowel effects that are mostly mild or moderate. The differences are in the detail.
| What the UK product information says | Mounjaro | Ozempic |
|---|---|---|
| Nausea and diarrhoea | Very common (more than 1 in 10 people) | Very common (more than 1 in 10 people) |
| Gallstones | Common (up to 1 in 10) in the weight management trials | Common (up to 1 in 10) |
| Acute pancreatitis | Uncommon (up to 1 in 100) | Uncommon (up to 1 in 100) |
| A sudden loss of vision called NAION | Not listed as of October 2026; the MHRA is reviewing other GLP-1 medicines (see below) | Very rare (up to 1 in 10,000) |
| The contraceptive pill | Can be less reliable for a while (see below) | Not expected to be affected |
| Stopping before a planned pregnancy | At least 1 month before | At least 2 months before |
| Who must never use it | Anyone allergic to tirzepatide or another ingredient | Anyone allergic to semaglutide or another ingredient |
Neither should be used in pregnancy. On eyesight, the MHRA has linked semaglutide to NAION in very rare reports and says it is reviewing the evidence for other GLP-1 medicines. Any sudden change in your vision needs same-day help, whichever medicine you take.
Contraception (Mounjaro only): tirzepatide can reduce absorption of the contraceptive pill. Use a non-oral method or add condoms for 4 weeks after starting and for 4 weeks after each dose increase.
Ozempic's product information says semaglutide is not expected to reduce the effect of the pill. Either way, tell your pharmacist or doctor which contraception you use.
In SURPASS-2, the most common side effects on both medicines were stomach and bowel effects, mostly mild to moderate: nausea affected 17% to 22% of people on tirzepatide and 18% on semaglutide 1mg, diarrhoea 13% to 16% and 12%, and vomiting 6% to 10% and 8%. Serious adverse events were reported in 5% to 7% of people on tirzepatide and 3% on semaglutide. Individual results vary. Everything about Mounjaro's own safety, from who should not take it to the rare serious risks, is in our guide Is Mounjaro safe?
How do Mounjaro and Ozempic doses compare?
They do not convert: a milligram of tirzepatide is not a milligram of semaglutide, so there is no Ozempic to Mounjaro conversion chart, and neither medicine's UK product information gives one, so a chart online that lines up an Ozempic dose with a Mounjaro dose is not one to follow.
Each medicine has its own steps. Mounjaro starts at 2.5mg once a week for 4 weeks, then goes up to 5mg. After that, the dose can go up in 2.5mg steps, each after at least 4 weeks on the current dose, to a maximum of 15mg. Ozempic starts at 0.25mg once a week for 4 weeks, which is not a dose to stay on, then goes up to 0.5mg. It can then go up to 1mg and to 2mg, each after at least 4 weeks, and weekly doses above 2mg are not recommended. Every Mounjaro step, pen by pen, is in our Mounjaro dosage chart.
Thinking about Mounjaro for weight management? Our consultation asks about your health and every medicine you take, including any GLP-1 medicine, and a GPhC-registered pharmacist reviews every answer before anything is supplied.
Check your eligibilityCan you switch from Ozempic to Mounjaro?
Yes, but only with advice from a healthcare professional, never on your own. The MHRA says to speak to one before switching between GLP-1 medicines, because they differ in strength, in how they are used and in what they are licensed for, and switching without advice may increase side effects or make treatment less effective.
If Ozempic was prescribed for your type 2 diabetes, your GP or diabetes team decides whether to change it. The NHS advises against stopping semaglutide suddenly, because with type 2 diabetes it can affect your blood sugar, and your team looks after your other diabetes medicines too. We can't supply through this service while you're on insulin or a sulphonylurea. GLP-1 treatment with insulin or a sulphonylurea can cause dangerously low blood sugar (hypoglycaemia). This needs to be managed by your GP or diabetes team, who can adjust your existing medicines at the same time. We do not supply Mounjaro to anyone with type 1 diabetes, and Ozempic's product information says semaglutide should not be used in type 1 diabetes either.
If you are moving from Ozempic to Mounjaro for weight management through Solira, this is how it works:
Tell us what you take now. Our consultation asks which GLP-1 medicine you use, your dose and the date of your last injection.
Your pharmacist chooses your first dose. Ozempic doses have no Mounjaro match, so the consultation suggests Mounjaro's licensed starting dose, 2.5mg. A GPhC-registered pharmacist reviews your answers and chooses your first dose before anything is supplied.
Never both at once. Do not take another Ozempic dose once you start Mounjaro. We never supply Mounjaro to be used alongside another GLP-1 medicine.
Step up gradually. Mounjaro goes up in 2.5mg steps, each after at least 4 weeks on your current dose, and your pharmacist reviews you before each increase.
More on moving between medicines is on our switching page and in our guide to switching between Mounjaro and Wegovy.
Can you take Mounjaro and Ozempic together?
No. Mounjaro and Ozempic should never be used at the same time. The UK product information for Wegovy, which contains semaglutide, the medicine in Ozempic, says semaglutide should not be used in combination with other GLP-1 medicines, and Mounjaro acts on the GLP-1 receptor too. We never supply Mounjaro to be used alongside another GLP-1 or weight-loss medicine, and our consultation asks about every one you take, so your pharmacist can check it has stopped before Mounjaro is supplied.
Where does Wegovy fit in?
Wegovy contains semaglutide, the same medicine as Ozempic, from the same maker, but it is licensed for weight management, at weekly doses up to 2.4mg, or 7.2mg for adults with a BMI of 30 or above. If you are comparing semaglutide with Mounjaro for weight loss, Wegovy is the one to compare: see what Wegovy is, Wegovy vs Ozempic and Mounjaro vs Wegovy.