0.25mg Wegovy vs 2.5mg Mounjaro: What's the Difference? (October 2026)

01 · The short answer

The verdict: same job, different medicines

Both doses are where treatment begins, and each is the lowest strength on its own ladder. The difference is the medicine, not just the number. Wegovy 0.25mg is semaglutide. Mounjaro 2.5mg is tirzepatide, which activates two natural gut-hormone receptors (GIP and GLP-1) rather than one.¹ The two scales are separate.

Both are licensed, effective weight-management treatments. Which suits you depends on your health profile, how you tolerate treatment and your prescriber's advice, not on the headline trial number alone.¹⁵

02 · Side by side

Wegovy 0.25mg and Mounjaro 2.5mg compared

The trial rows describe the final maintenance doses of each medicine over many weeks. They say nothing about what the starter pens alone achieve. Trial averages do not predict your own result.

03 · Choosing

Who each option may suit

Wegovy may suit someone whose prescriber prefers a single-action GLP-1 medicine, or who has already tolerated semaglutide. Mounjaro may suit someone whose prescriber prefers the dual-action option. Neither choice is final. Your prescriber can review how you are getting on at each step.

Cost is a practical factor too. Your first 2.5mg Mounjaro pen is £129.99 with code FIRST40, against a standard price of £169.99. After that, every later order is £25 off the standard price (code DOSE25). Wegovy's first pen is £99.99 on a first order. The UK Wegovy and Mounjaro comparison sets this out further.

When you are ready, start your free consultation. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

04 · Mechanism compared

How semaglutide and tirzepatide work differently

The core difference between the two starter pens is the medicine inside them. Wegovy contains semaglutide, a single-action GLP-1 medicine. Mounjaro contains tirzepatide, which is the first treatment of its kind to activate two natural gut-hormone receptors at once: GIP and GLP-1.¹ That dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide.¹

Together, the two receptor actions 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.¹ Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

Why the milligrams do not line up

It is natural to see 0.25 and 2.5 and assume one is ten times the other. That reading is wrong. The two medicines are different molecules with different dose ladders, so the numbers cannot be matched. A Wegovy 0.25mg pen and a Mounjaro 2.5mg pen cannot be matched by arithmetic. There is no licensed direct conversion between semaglutide and tirzepatide.¹

You can read more in our explainer on the difference between 2.5mg and 5mg Mounjaro.

How long they stay in the body

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 This matters if you are thinking of switching, because your prescriber will plan the gap between medicines.

What the head-to-head evidence adds

In SURMOUNT-5, 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. The gap shows up at the full maintenance doses, not at the starter pens, so it should not be read as a verdict on 0.25mg versus 2.5mg.

For a deeper look at the two active ingredients, see our guides on the difference between sema and tirzepatide and on semaglutide versus tirzepatide. If you are comparing with an older once-weekly diabetes medicine, the dulaglutide and tirzepatide comparison is the one to read.

05 · Dose ladders

How the Wegovy and Mounjaro dose ladders work

Each starter pen is the bottom rung of a ladder, and the ladders are built differently. Wegovy pens come in 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg, given once weekly. The dose steps up after 4 weeks on each of 0.25mg, 0.5mg, 1mg and 1.7mg, and the 2.4mg maintenance dose starts from week 17.¹⁸ The 2.4mg dose is the licensed maintenance dose for weight management.¹⁸

Mounjaro is a once-weekly injectable supplied as a pre-filled multi-dose KwikPen in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹ Each pen covers four weeks. Your prescriber decides whether you move up, hold, or settle at a lower strength.

Is 1.7mg Wegovy strong?

Wegovy 1.7mg is the fourth of five steps, one step below the 2.4mg licensed maintenance dose.¹⁸ It is a higher rung than 0.25mg, but it is not the top of the ladder. Your prescriber should guide whether you hold at a step or go on.

Why a starter dose exists at all

Both ladders are designed so treatment begins at the lowest strength and steps up in stages rather than starting at the top. The starter pens are where you and your prescriber see how you respond. That is the safe way to read both 0.25mg and 2.5mg: an introduction to the ladder, not a destination. Any change in dose belongs with your prescriber.

Counting up the Mounjaro pens

At standard prices before discounts, if you step up after 4 weeks on each dose, your first four pens (2.5mg to 10mg) cost £959.96. A new customer's first order is £40 less, and every later order is £25 less. A first year (13 pens) costs £2,711.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,599.88 if you step up through every dose to 15mg. For 7.5mg, 10mg or 12.5mg, the monthly prices are £279.99, £290.99 and £319.99 respectively. These are standard prices before any discount.

You can see current pricing for the Mounjaro pen on the product page.

06 · Trial evidence

What the trials show for each medicine

The trials tell you about full treatment courses, not about the two starter pens. Read them as averages. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity.

SURMOUNT-5: the first large head-to-head

SURMOUNT-5 is the first large head-to-head trial of the two medicines. It enrolled 751 adults who took tirzepatide or semaglutide 2.4mg for 72 weeks.¹⁵ Average loss was 22.8 kg on tirzepatide versus 15.0 kg on semaglutide. The proportions who reached each threshold were:

• At least 10% of body weight: 81.6% on tirzepatide vs 60.5% on semaglutide.
• At least 15%: 64.6% vs 40.1%.
• At least 20%: 48.4% vs 27.3%.
• At least 25%: 31.6% vs 16.1%.¹⁵

For a worked example, someone starting at 100 kg who lost 20.2% would lose about 20 kg. A person on semaglutide losing 13.7% would lose about 14 kg. These are straight arithmetic from trial averages, not predictions for you.

SURMOUNT-1: tirzepatide on its own

In SURMOUNT-1, 2,539 adults on tirzepatide alongside diet and exercise lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20%.²

STEP 1: semaglutide on its own

In STEP 1, adults on semaglutide 2.4mg (Wegovy) lost on average 14.9% of body weight over 68 weeks, compared with 2.4% on placebo.⁹ In the same trial, 86.4% lost at least 5% of body weight (vs 31.5% on placebo), 69.1% lost at least 10% (vs 12.0%) and 50.5% lost at least 15% (vs 4.9%).⁹

How to read these without over-reading

Do not set the SURMOUNT-1 and STEP 1 numbers side by side as if they were head to head. They were different trials with different designs. Only SURMOUNT-5 supports a direct comparison, and it compares the maintenance doses. Neither trial reports what the first pen alone does, so nobody can honestly say what 0.25mg versus 2.5mg will do for you.

If you want to see how the evidence compares for other treatments, our page on the difference between orlistat and Mounjaro shows another contrast.

07 · Side effects

Side effects, stopping and the downsides

The most common side effects of either medicine are digestive, and the trial data show this for Wegovy. In STEP 1, gastrointestinal side effects were reported by 74.2% of people on semaglutide 2.4mg, compared with 47.9% on placebo. 7.0% stopped treatment because of side effects, compared with 3.1% on placebo.⁹

Mounjaro side effects

The most common side effects, affecting more than 1 in 10 people, are nausea, diarrhoea, vomiting, constipation and abdominal discomfort. Side effects are most likely when starting treatment or moving up a dose, and for most people they ease within days to a few weeks.¹³ Different trials and designs mean the Wegovy and Mounjaro numbers cannot be set against each other.

Starting doses and tolerance

Starting at the lowest dose lets you and your prescriber see how you respond before stepping up. That applies equally to 0.25mg Wegovy and 2.5mg Mounjaro. If side effects are hard to manage, tell your prescriber rather than changing the schedule yourself.

What to avoid while taking Mounjaro

The clearest rule is about combinations. 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. Beyond that, tell your prescriber about every medicine you take, including insulin or sulfonylureas, where doses may need adjusting.¹³

Reporting a problem

If you notice a new or lasting symptom, tell your prescriber. You can also report suspected side effects through the MHRA Yellow Card scheme.¹⁹ Our team provides ongoing monthly reviews, dose-titration and follow-up assessments, plus side-effect support, so you are not left to manage things alone.

08 · Switching safely

Switching between Wegovy and Mounjaro

If you are on Wegovy and thinking of Mounjaro, there is no licensed direct conversion between semaglutide and tirzepatide.¹ That means you cannot translate a Wegovy dose into a Mounjaro dose by formula. Switching is done under prescriber supervision. Typically the previous medicine is stopped, a washout interval is observed, and Mounjaro is started at a dose your prescriber judges appropriate. This is often the 2.5mg starting dose, sometimes adjusted based on your history.¹

Never run two at once

Never run two GLP-1 medicines together. The overlap has no safety data behind it. If you have leftover pens of one medicine, do not use them alongside the other. Tell the prescriber exactly what you have taken and when your last dose was.

What your prescriber will ask

Expect questions about your current Wegovy dose, how long you have taken it, how well you tolerated it, and why you want to change. They will also want to know about your health history and any other medicines. The answers shape the starting dose and the interval between medicines. There is no one-size rule, which is why this must be a prescriber decision.

Switching and the discount

New customers can use code FIRST40 for £40 off their first order at any dose, including people moving from another provider at a higher dose. If you are switching to us at 15mg, your first order is £289.99. That is a first-order price, not a monthly one. After that, every later order is £25 off the standard price (code DOSE25).

Switching in the other direction

Some people move from Mounjaro to Wegovy, for example because of tolerance or because their prescriber suggests it. Wegovy's licensed dose ladder starts at 0.25mg, and your prescriber decides when to switch and which dose to start on.¹⁸ You can read about it on the Wegovy pen page.

Stacking and shortcuts

Anyone offering a quick route, such as stacking two products, research peptides or compounded copies, sits outside a regulated supply chain. Those options carry no safety data. Stay on a licensed pathway reviewed by a GPhC-registered prescriber.

09 · Cost and NHS

Cost over time and the NHS picture

Across the UK pharmacies we track, the cheapest and dearest 2.5mg starting pens are £143.96 and £179.99, checked 11 October 2026. The smallest and largest gaps between providers for the same dose run from £27 to £41.

Planning a year

At standard prices before discounts, if you step up after 4 weeks on each dose, your first four Mounjaro pens (2.5mg to 10mg) cost £959.96. A first year costs £2,711.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,599.88 if you step up through every dose to 15mg. A new customer's first order is £40 less, and every later order is £25 less. Payment can be by Visa or Mastercard, or Klarna and pay-monthly options. There are no subscriptions.

NHS access

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, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting. NHS access to Wegovy runs through specialist weight-management services; ask your GP. On the NHS, the prescription charge in England is £9.90 per item where it applies, though you should check your own circumstances.

What you get when you order privately

The consultation is free, and the price shown is the price paid, with no hidden fees. Mounjaro comes through official LillyDirect supply, direct from Eli Lilly's UK distribution, as genuine KwikPens, with all six doses stocked and currently in stock. Delivery is free next-day tracked, in temperature-controlled packaging, with same-day dispatch when ordered by 3pm. Saturday delivery is £14.99. Needles, a sharps bin and injection guidance come with every order. Repeat orders re-check suitability, with no auto-shipping.

The full range of weight loss treatments shows other options if neither pen fits.

10 · Pills and Ozempic

Pills, Ozempic and other options

Can you take Mounjaro as a pill?

No. There is no tablet form of Mounjaro, because tirzepatide is injection-only in the UK. Two GLP-1 weight-loss tablets are now licensed in the UK, though. Wegovy tablets (oral semaglutide, made by Novo Nordisk) were approved by the MHRA in June 2026. Foundayo (orforglipron, made by Eli Lilly) was approved in August 2026.²⁰²¹ They are different medicines from Mounjaro, with their own dosing, eligibility checks and trial results, and both are prescription-only.

Which pill is better, Mounjaro or Wegovy?

The question mixes two things. Mounjaro is not a pill. Wegovy comes as a once-weekly pen and now also as a tablet. Tablet trial results should not be set against Mounjaro's as if head to head, because they were separate trials. If a tablet appeals to you, see the current Wegovy tablet details on the product page and discuss it with a prescriber.

What is 9mg Wegovy pill equivalent to in Mounjaro?

There is no licensed equivalence. The tablet and the injection are different formulations, and there is no licensed direct conversion between semaglutide and tirzepatide. A prescriber works out any switch individually, so do not try to match numbers yourself.

Is Wegovy the same as Ozempic?

Both contain semaglutide, but they are not licensed for the same purpose. 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).¹⁸ So Mounjaro versus Ozempic for weight loss is really Mounjaro versus Wegovy, and a regulated UK pharmacy will not supply Ozempic for weight loss.

Other licensed options

Orlistat (a tablet) blocks some dietary fat absorption and produces smaller average losses. Wegovy and Saxenda (liraglutide) are other licensed injectables. Liraglutide is supplied at 6mg per millilitre and is a daily injection, unlike the once-weekly Mounjaro and Wegovy.

Supplements are not substitutes

"Natural GLP-1" supplements such as berberine are not medicines, are not regulated for this use and have no comparable trial evidence. They are low-cost supplements with no clinical oversight, and dosing is not standardised. Dramatic weight-loss claims on such products are a warning sign.

11 · Ordering and aftercare

How to start safely with Mounjaro

If you have decided Mounjaro suits you, ordering follows four steps, and a prescriber reviews each request. Mounjaro 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.

The four steps

• Free online consultation. A short health questionnaire, with no charge and no obligation.
• Prescriber review. A GPhC-registered prescriber reviews it, not a scoring script. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• Dispensing and dispatch. Our registered pharmacy dispenses it, with same-day dispatch when ordered by 3pm.
• Delivery. Free next-day tracked delivery with DPD, in temperature-controlled, discreet packaging.

You can begin with the free consultation, or look at the Mounjaro pen prices and consultation page first.

Genuine supply matters

Counterfeit pens are a real risk when people shop on price alone. Be wary of anyone offering to supply without a consultation or prescription. We are a GPhC-registered pharmacy (registration 9012878) and you can check it on the GPhC register. Our Mounjaro comes through official LillyDirect supply, direct from Eli Lilly's UK distribution. The MHRA publishes counterfeit medicine alerts, and suspected problems can be reported through the Yellow Card scheme.⁷

Support after you start

Aftercare includes ongoing monthly reviews, dose-titration and follow-up assessments by the prescribing team, and side-effect support. Our team is available Monday to Friday, 9am to 5pm, by email at support@everydaymeds.co.uk, through account portal chat, or by phone on 0333 207 0413. The free GLPTrackr companion app (iOS and Android) helps you track your GLP-1 journey. More than 100,000 customers have been supported, and that figure reflects customers served, not how well treatment works.

Refunds

Declined consultations are refunded automatically in full. Dispensed prescription medicines cannot be returned unless they are faulty, damaged or the wrong item, in which case contact us within 3 days. Refunds take 5–10 working days.

This page is information, not a substitute for medical advice.

12 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or 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) — your prescriber may need to adjust those medicines.¹