Mounjaro Switch to Wegovy: How It Works (October 2026)

01 · The short verdict

Should you switch from Mounjaro to Wegovy?

Switch only if there is a reason, and only with a prescriber's agreement. Both are effective, licensed weight-management medicines, and the choice depends on your health profile, tolerance and prescriber advice, not the headline number alone.¹⁵

Mounjaro may suit people who are tolerating it well and responding to it. Wegovy suits people whose prescriber feels semaglutide fits their history better, who did not tolerate tirzepatide, or who simply prefer it. If you are doing well on Mounjaro, there is no clinical need to move.

If you started on Wegovy and are wondering about the opposite move, our guide to going from Wegovy to Mounjaro covers that direction, and the switch timeline guide shows what to expect week by week.

02 · Side by side

Mounjaro vs Wegovy at a glance

SURMOUNT-5 was the first large head-to-head trial of the two; the other trial figures are shown for each medicine separately and should not be set against each other.

Trial averages do not predict your own result. Both medicines work alongside a reduced-calorie diet and increased physical activity.

03 · Deciding

What should drive your decision

Five factors matter more than any single statistic.

• Tolerance: if side effects on Mounjaro are the problem, tell your prescriber. They may adjust the dose before suggesting a change of medicine.
• Response: trial averages hide a wide spread. Your own progress over several months is a better guide.
• Cost: compare monthly cost at the dose you would actually use, not only the first pen. Our Wegovy switch pricing guide sets this out.
• Dose history: a high Mounjaro dose does not mean you start Wegovy high; your prescriber judges the starting point.
• Reversibility: moving back is possible, as explained in can I switch back.

04 · How a switch works

How a Mounjaro to Wegovy switch works in practice

There is no licensed direct conversion between tirzepatide and semaglutide, so the switch is individual to you and done under prescriber supervision.¹ Your prescriber decides when to switch and which Wegovy dose to start on; Wegovy's licensed dose ladder starts at 0.25mg.

Two facts are useful to know. Tirzepatide has a half-life of about five days, so 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 Wegovy, meanwhile, is licensed to start low and climb: 0.25mg, 0.5mg, 1mg, 1.7mg, then 2.4mg, with each step lasting 4 weeks, reaching maintenance from week 17.¹⁸

Your prescriber chooses the timing from your last injection date, current dose and side-effect history.

Our Mounjaro switch guide covers the general principles of changing between treatments.

05 · Dose equivalence myth

Is 1mg Wegovy equivalent to Mounjaro?

No dose of Wegovy is officially equivalent to any Mounjaro strength, because the two medicines are different molecules with different mechanisms.¹ Tirzepatide activates GIP and GLP-1 receptors; semaglutide acts on GLP-1 alone. Milligram numbers cannot be compared across them.

That also answers 'is 1mg of Wegovy strong?'. It is the third step on the ladder, below the 1.7mg and 2.4mg doses, and 2.4mg is the licensed maintenance dose for weight management.¹⁸ Whether 1mg is 'strong' for you depends on your tolerance, not on a Mounjaro comparison.

If you are currently on 5mg, for example, the 5mg Mounjaro to Wegovy guide explains how prescribers think about that specific starting point.

06 · Is Wegovy stronger?

Is Wegovy stronger than Mounjaro?

On average weight loss, no: the first large head-to-head trial found more loss with tirzepatide. 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 Individual results vary.

The detail is in the thresholds. In SURMOUNT-5, 751 adults took one or the other for 72 weeks.¹⁵ At least 10% of body weight was lost by 81.6% on tirzepatide vs 60.5% on semaglutide; at least 15% by 64.6% vs 40.1%; at least 20% by 48.4% vs 27.3%; and at least 25% by 31.6% vs 16.1%. Average loss was 22.8 kg vs 15.0 kg.

To put that in kilograms, for someone starting at 100 kg, 20.2% is about 20 kg and 13.7% is about 14 kg. That is straight arithmetic on trial averages, not a prediction.

Wegovy remains an effective treatment. In STEP 1, adults on semaglutide 2.4mg lost on average 14.9% of body weight over 68 weeks, compared with 2.4% on placebo.⁹

07 · Wegovy downsides

What is the downside of Wegovy, and why do people stop?

The main documented downside is gastrointestinal side effects. In STEP 1, these were reported by 74.2% of people on semaglutide 2.4mg compared with 47.9% on placebo, and 7.0% stopped treatment because of side effects, compared with 3.1% on placebo.⁹

That is one measured reason people stop. Cost, supply and personal preference all play a part in real life, and your prescriber is the right person to talk through yours.

If you notice a new symptom on either medicine, tell your prescriber and report it through the Yellow Card scheme.¹⁹

08 · What not to do

What not to do when switching

Never run two GLP-1 medicines together.¹

Mounjaro also must not be combined with unlicensed 'research' peptides such as retatrutide, which has no UK licence, or with compounded copies. These have no safety data and no regulated supply chain. Anything that promises faster results outside a licensed pathway is a warning sign.¹

Do not rely on Ozempic as a stand-in either. It is semaglutide licensed for type 2 diabetes, not a UK weight-loss medicine, and a regulated UK pharmacy will not supply it for weight loss. The licensed weight-management options are Mounjaro and Wegovy.¹⁸

Tablets are a separate route. There is no tablet form of Mounjaro, but Wegovy tablets are now licensed in the UK as a different product with its own dosing and eligibility checks. For current Wegovy tablet prices, see our weight loss treatments page.²⁰

09 · Switching with us

Switching provider or medicine with EverydayMeds

Start with a free online consultation, reviewed by a GPhC-registered prescriber. You tell them your current medicine, dose, last injection date and any side effects, and they decide what is suitable. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

Whichever way you go, supply is dispensed by our registered pharmacy. Mounjaro comes from official LillyDirect supply, and all six doses are in stock. Orders placed by 3pm are dispatched the same day, with free next-day tracked delivery in temperature-controlled packaging.

New customers save £40 on their first order with code FIRST40, at any dose, and an automatic £25 reorder discount applies to every future order (code DOSE25). A first Mounjaro year costs £2,399.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,279.88 if you step up through every dose to 15mg, at standard prices before those discounts.

If you are only changing supplier rather than medicine, read about a Mounjaro switch of provider or compare options on our switch provider page. You can start your free consultation whenever you are ready.

10 · 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