Is Wegovy or Mounjaro Better for Weight Loss? (October 2026)

01 · The verdict

Which is better for weight loss, Wegovy or Mounjaro?

On average, Mounjaro produced more weight loss than Wegovy in the head-to-head evidence. In SURMOUNT-5, 751 adults took tirzepatide or semaglutide 2.4mg (Wegovy) for 72 weeks. Average loss was 20.2% of body weight on tirzepatide versus 13.7% on semaglutide.¹⁵ In kilograms, that was 22.8 kg versus 15.0 kg on average.¹⁵

Put simply: for someone starting at 100 kg, 20.2% is about 20 kg and 13.7% is about 14 kg. These are trial averages, and individual results vary. Both are effective, licensed treatments. Which suits you depends on your health profile, tolerance and prescriber advice, not the headline number alone.¹⁵

Our fuller side-by-side is in Wegovy against Mounjaro for weight loss. If you want the effectiveness question answered in more depth, see which is more effective.

02 · Side by side

Mounjaro and Wegovy compared

Later doses cost more, so the monthly figure changes as you step up. Our Wegovy pen page shows current prices for each Wegovy strength.

03 · Deciding

Who each medicine tends to suit

Mounjaro may suit people whose prescriber considers the higher average weight loss in SURMOUNT-5 relevant. That is the clearest result from SURMOUNT-5, where more participants on tirzepatide reached each loss threshold.¹⁵ It also suits people who want a choice of six strengths to fine-tune their dose with a prescriber.

Wegovy can suit people whose prescriber prefers a single-action GLP-1 medicine, who have already done well on it, or who tolerate it comfortably. A person doing well on Wegovy has no need to switch just because Mounjaro averages more.

In practice, three factors decide: how you tolerate the medicine, your medical history, and the cost you can sustain over months. A prescriber weighs these with you. The free consultation is reviewed by a GPhC-registered prescriber, and you can start your free consultation without obligation.

04 · How they work

How Mounjaro and Wegovy work

Both medicines mimic natural gut hormones, but Mounjaro acts on two receptors and Wegovy on one. Tirzepatide activates both GIP and GLP-1 receptors. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹

In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet. This dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide, the active ingredient in Wegovy.¹

Both are once-weekly injections. Wegovy steps up after at least 4 weeks through 0.25mg, 0.5mg, 1mg and 1.7mg, reaching the 2.4mg maintenance dose from week 17.¹⁸ Mounjaro comes in six strengths from 2.5mg to 15mg, and your prescriber decides when to step up.¹ Neither works instead of lifestyle change; both are used alongside a reduced-calorie diet and increased physical activity.

05 · The trial evidence

What the trials show in detail

The detailed SURMOUNT-5 results show a consistent gap at every threshold, but both groups lost meaningful weight. 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%.¹⁵

The Wegovy trial that led to its licence was 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 In that trial, 86.4% lost at least 5% of body weight, 69.1% lost at least 10% and 50.5% lost at least 15%, against 31.5%, 12.0% and 4.9% on placebo.⁹

For Mounjaro, the main weight-loss trial was SURMOUNT-1, in 2,539 adults. Over 72 weeks, people on tirzepatide lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg, compared with 3.1% with lifestyle changes alone.² At 72 weeks, 85% on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5%.²

Do not line up SURMOUNT-1 and STEP 1 against each other. They were different trials with different participants and lengths. Only SURMOUNT-5 compares the two medicines directly, and trial averages do not predict your own result.

06 · Side effects

Side effects, tolerance and stopping

Stomach and gut side effects are the main tolerance issue with Wegovy. In STEP 1, gastrointestinal side effects were reported by 74.2% of people on semaglutide 2.4mg, compared with 47.9% on placebo. Also, 7.0% stopped treatment because of side effects, compared with 3.1% on placebo.⁹

Tolerance is personal. Some people do better on one than the other, which is why a prescriber reviews your dose and symptoms during treatment rather than leaving it to a headline number.

If you have new or worrying symptoms, speak to your prescriber. For severe, persistent stomach pain, swelling of the face, lips, tongue or throat, or difficulty breathing, get medical help straight away. You can also report suspected side effects through the MHRA Yellow Card scheme.¹⁹ For a safety-focused view, see our guide on which is safer.

07 · Cost

Cost: Mounjaro and Wegovy compared

Price depends on dose, and it rises as you step up on either medicine. Your first 2.5mg Mounjaro pen costs £129.99 with code FIRST40 (standard price £169.99). Your first Wegovy pen costs £99.99. Each pen lasts four weeks.

New customers get £40 off a first order at any dose, with code FIRST40. An automatic £25 reorder discount applies to every future order (code DOSE25). Every later Mounjaro order is therefore £25 off the standard price of that dose.

For planning, the first four pens of Mounjaro (four pens: 2.5mg, 5mg, 7.5mg and 10mg) cost £879.96 at standard prices. A first year (13 pens) costs £2,399.88 if you settle at 5mg, up to £3,279.88 at 15mg. A new customer's first order is £40 less and every later order £25 less. The consultation is free and the price shown is the price paid.

08 · NHS access

NHS access to Mounjaro

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. For Wegovy, NHS access runs through specialist weight-management services; ask your GP.

09 · Switching

Switching from Wegovy to Mounjaro

There is no licensed direct conversion between semaglutide and tirzepatide, so any switch 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. That is often the 2.5mg starting dose, sometimes adjusted based on your history.¹

Never run two GLP-1 medicines together. Mounjaro must also not be combined with 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 you are switching to us from another provider at a higher dose, the new-customer discount applies to your first order at any dose. Switching at 15mg? Your first order is £259.99. For the wider picture, see whether Mounjaro or Wegovy works better for people in your position.

10 · Ozempic and tablets

Ozempic, tablets and other options

Ozempic is not a UK weight-loss medicine. It is semaglutide licensed for type 2 diabetes, and prescribing it privately for weight loss is off-label. The licensed weight-management options are Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg), so "Mounjaro or Ozempic" for weight loss is really Mounjaro versus Wegovy. A regulated UK pharmacy will not supply Ozempic for weight loss. You can read more in semaglutide against Mounjaro.

There is no tablet form of Mounjaro. Two GLP-1 weight-loss tablets are now licensed in the UK: Wegovy tablets (oral semaglutide), approved by the MHRA in June 2026, and Foundayo (orforglipron, made by Eli Lilly), approved in August 2026.²⁰²¹ They are different medicines with their own dosing, eligibility checks and trial results. See current Wegovy tablet prices on the product page rather than assuming they match the injection.

Orlistat is a tablet that blocks some dietary fat absorption and produces smaller average losses; see orlistat or Wegovy. "Natural GLP-1" supplements such as berberine are low-cost supplements with no clinical oversight and no comparable trial evidence.

11 · Getting started

How to start treatment with us

Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. We are a GPhC-registered UK online pharmacy (registration 9012878), and our Mounjaro comes through official LillyDirect supply, with genuine KwikPens.

• Free online consultation: a short health questionnaire, no charge and no obligation.
• Prescriber review: reviewed by a GPhC-registered prescriber. Unsuitable orders are refunded automatically.
• Dispatch and delivery: same-day dispatch when ordered by 3pm, then free next-day tracked delivery in temperature-controlled packaging. Saturday delivery is £14.99.

Ongoing monthly reviews are included, and repeat orders re-check suitability with no auto-shipping. To compare other routes first, see all weight loss treatments.

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.

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