Difference Between Ozempic and Mounjaro in the UK (October 2026)

01 · The verdict

Which is right for you: Ozempic or Mounjaro?

Which medicine is right depends on why you need treatment, and that is a decision for your prescriber. Ozempic is semaglutide licensed for type 2 diabetes, so prescribing it privately for weight loss is off-label. The licensed weight-management options are Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg).¹¹⁸ A regulated UK pharmacy will not supply Ozempic for weight loss.

So the useful question is usually Mounjaro versus Wegovy, because both are licensed for the same purpose. We cover that head-to-head in our guide to the difference between Mounjaro and Wegovy.

• Mounjaro is licensed for weight management and type 2 diabetes. Whether tirzepatide suits you is for your prescriber to judge from your health profile.
• Wegovy is the licensed semaglutide option for weight management. Your prescriber decides whether it suits your history and tolerance.
• Ozempic is licensed for type 2 diabetes. For people with that condition, the decision sits with their diabetes team.

02 · Side by side

Ozempic vs Mounjaro comparison table

Weight-loss trial results are shown for the licensed semaglutide product, Wegovy, because Ozempic is not licensed for weight loss.

Trial averages do not predict your own result, and treatment works alongside a reduced-calorie diet and more physical activity. There is no tablet form of Mounjaro; tirzepatide is injection-only in the UK.

03 · Deciding

The factors that should decide it

Your reason for treatment comes first. Type 2 diabetes treatment sits with your diabetes team, and Ozempic is licensed for it. Weight management is a different pathway, with Mounjaro and Wegovy as the licensed injectables.

Next is how you tolerate treatment. A prescriber looks at your history, other medicines and goals before choosing. That is why the consultation matters more than any headline number.

Finally, cost and access. You can read how the two medicines compare on cost in our price comparison guide.

04 · How they work

How Ozempic and Mounjaro work differently

Mounjaro contains tirzepatide, which activates two natural gut-hormone receptors at once: GIP and GLP-1.¹ Together these help regulate appetite, slow how quickly the stomach empties and improve the way the body responds to insulin. In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.

Tirzepatide's dual action distinguishes it from single-action GLP-1 medicines such as semaglutide, the ingredient in Wegovy and Ozempic.¹¹⁸

In short, the difference between Ozempic and tirzepatide is different molecules, one receptor target versus two, and different licences. The mechanism difference does not by itself tell you which will suit you, which is why a prescriber reviews your history first.

Tirzepatide has a half-life of about five days. After a final dose it takes roughly 4–5 weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears.¹

05 · Licensing and off-label use

Why licensing matters for weight loss

Ozempic is semaglutide licensed for type 2 diabetes. It is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label. The licensed weight-management options are Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg).¹¹⁸

So "Mounjaro vs Ozempic" for weight loss is really Mounjaro vs Wegovy. A regulated UK pharmacy will not supply Ozempic for weight loss. If a seller offers to supply Ozempic for weight loss without a consultation or prescription, treat that as a warning sign.

Why does this matter in practice? A licensed product has been assessed for the specific purpose, dose range and population it is used for. Off-label use sits outside that assessment. For weight management you want a medicine, dose ladder and monitoring designed for that goal.

Our existing guide on whether Ozempic and Mounjaro work for weight loss in the UK goes through the same point with a focus on everyday questions.

06 · What the trials show

What the trial evidence shows

The first large head-to-head trial of tirzepatide and semaglutide for weight loss is SURMOUNT-5. In it, adults on tirzepatide lost on average 20.2% of body weight over 72 weeks versus 13.7% on semaglutide 2.4mg (Wegovy).¹⁵ Both are effective, licensed treatments. Which suits you depends on your health profile, tolerance and prescriber advice, not the headline number alone.

In more detail, SURMOUNT-5 enrolled 751 adults for 72 weeks. At least 10% of body weight was lost by 81.6% on tirzepatide versus 60.5% on semaglutide. At least 15% was lost by 64.6% versus 40.1%, at least 20% by 48.4% versus 27.3%, and at least 25% by 31.6% versus 16.1%. Average loss was 22.8 kg versus 15.0 kg.¹⁵

Semaglutide 2.4mg has its own trial. In STEP 1, adults on Wegovy lost on average 14.9% of body weight over 68 weeks, compared with 2.4% on placebo.⁹ There, 86.4% lost at least 5% of body weight (31.5% on placebo), 69.1% lost at least 10% (12.0%) and 50.5% lost at least 15% (4.9%).⁹ Only SURMOUNT-5 supports a direct comparison, so STEP 1 is not set against other trials.

For Mounjaro on its own, SURMOUNT-1 followed 2,539 adults. Alongside diet and exercise they lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, versus 3.1% with lifestyle changes alone.² As a worked example, for someone starting at 100 kg, 20.9% is about 21 kg. These are trial averages and individual results vary.

At 72 weeks, 85% on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of body weight. Half of participants on 10mg and 57% on 15mg lost at least 20%.²

07 · Switching safely

Switching from Ozempic to Mounjaro

Switching is done only under prescriber supervision. There is no licensed direct conversion between semaglutide and tirzepatide. Typically the previous medicine is stopped, a washout interval is observed, and Mounjaro is started at a dose your prescriber judges appropriate. That is often the 2.5mg starting dose, and sometimes it is adjusted based on your history.

Never run two GLP-1 medicines together. Mounjaro must not be combined with other GLP-1 medicines, unlicensed "research" peptides (such as retatrutide, which has no UK licence) or compounded copies. These combinations have no safety data and no regulated supply chain. If something promises faster results outside a licensed pathway, that is the warning sign.

If you take Ozempic for type 2 diabetes, speak to your diabetes team before changing anything. Do not stop a diabetes medicine on your own.

Your prescriber decides your starting dose in our free consultation.

08 · Side effects and safety

Side effects and safety

Both medicines can cause side effects; ask your prescriber or pharmacist about any that concern you. For Mounjaro, most side effects are digestive. The most common, affecting more than 1 in 10 people, are nausea, diarrhoea, vomiting, constipation and abdominal discomfort. They are most likely when starting treatment or moving up a dose, and for most people they ease within days to a few weeks as the body adjusts.¹³

For Wegovy, STEP 1 reported gastrointestinal side effects in 74.2% of people on semaglutide 2.4mg versus 47.9% on placebo, and 7.0% stopped treatment because of side effects versus 3.1% on placebo.⁹

Serious side effects are uncommon but need urgent attention. Get medical help straight away for severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis). Get medical help straight away for pain in the upper right abdomen, fever or yellowing of the skin or eyes (possible gallbladder problems). Get medical help straight away for signs of a severe allergic reaction, such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion), as your prescriber may need to adjust those medicines.¹³

For any new or lasting symptom, tell your prescriber. You can also report a suspected side effect through the MHRA Yellow Card scheme.¹⁹ Our team provides ongoing monthly reviews and side-effect support once you start.

09 · Cost and NHS access

Cost, NHS access and tablet options

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition. The NHS primary-care rollout began in June 2025 with the highest-need groups first, initially BMI 40+ with four or more qualifying conditions.⁴⁶ Full rollout is expected to take years.

Privately, the standard price of a Mounjaro pen (four weeks) is £169.99 at 2.5mg and rises with each dose to £329.99 at 15mg, shown live on the Mounjaro pen page. A new customer's first order is £40 off with code FIRST40, and an automatic £25 reorder discount applies to every future order (code DOSE25). If you step up after 4 weeks on each dose, your first four pens (2.5mg to 10mg) cost £959.96 at standard prices, before those discounts.

Across the UK pharmacies we track, Mounjaro pens range from £143.96 to £339.00 per month at standard prices, checked 10 October 2026.

If you are weighing Wegovy, the first pen on the Wegovy pen page costs £99.99 on a first order.

There is no tablet form of Mounjaro. Two GLP-1 weight-loss tablets are now licensed in the UK: Wegovy tablets (oral semaglutide) and Foundayo (orforglipron). They are different medicines with their own dosing, eligibility checks and trial results, and both are prescription-only. See current Wegovy tablet prices on the product page. Orlistat is a tablet that blocks some dietary fat absorption and produces smaller average losses; our guide explains the difference between orlistat and Mounjaro.

10 · Other alternatives

Other options people compare

Saxenda (liraglutide) is another licensed injectable, but it is a daily injection supplied at 6mg per millilitre, unlike once-weekly Mounjaro and Wegovy. Our guide to the difference between Mounjaro and Saxenda covers it. If you are weighing a tablet form of semaglutide, read about the difference between Mounjaro and Rybelsus.

"Natural GLP-1" supplements, sometimes called a "poor man's Ozempic", are not medicines. They are not regulated for this use and have no comparable trial evidence. They are available cheaply without assessment, with no clinical oversight, and dosing is not standardised. Dramatic weight-loss claims made for them should be treated with caution.

Browse everything we offer on our weight loss treatments page. A prescriber can explain which licensed option, if any, suits you.

11 · How to order

How ordering Mounjaro works

Ordering takes four steps, and the consultation is free. We are a GPhC-registered UK online pharmacy (registration 9012878), and Mounjaro is supplied through official LillyDirect supply, direct from Eli Lilly's UK distribution.

• Free online consultation: a short health questionnaire with no charge and no obligation.
• Prescriber review: reviewed by a GPhC-registered prescriber, not a scoring script. If the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• Dispensing and dispatch: dispensed by our registered pharmacy, with same-day dispatch when ordered by 3pm.
• Delivery: free next-day tracked delivery in discreet, temperature-controlled packaging. Saturday delivery is £14.99.

All six doses are in stock. Needles, a sharps bin and injection guidance come with every order. Repeat orders re-check suitability, with no auto-shipping and no subscription lock-in. Our companion app, GLPTrackr, is free for tracking your journey. Read our broader guide, what is the difference between Mounjaro and Wegovy, or the Wegovy and Mounjaro UK comparison, before you decide.

Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary. This page is information, not a substitute for medical advice.