Is Ozempic Semaglutide or Tirzepatide? (October 2026)

01 · The short answer

Ozempic is semaglutide: the brand and the ingredient explained

Ozempic is a brand name, and the ingredient inside it is semaglutide. Tirzepatide is a different ingredient, sold in the UK under the brand name Mounjaro.¹ Ozempic and Mounjaro are simply the brand names you may meet on a pharmacy shelf.

A quick way to remember it: semaglutide sits behind both Ozempic and Wegovy. Tirzepatide sits behind Mounjaro. The question "is semaglutide Mounjaro or Ozempic?" therefore has a clear answer: semaglutide is Ozempic (and Wegovy), and Mounjaro is tirzepatide.

02 · Your next step

What this means if you want weight-loss treatment

If your goal is weight management, Ozempic is not the product to look for. It is semaglutide licensed for type 2 diabetes, and prescribing it privately for weight loss is off-label. A regulated UK pharmacy will not supply Ozempic for weight loss.¹⁸

The licensed choices are Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg). So a "Mounjaro vs Ozempic" question for weight loss is really Mounjaro versus Wegovy. We cover that in our semaglutide or Mounjaro guide, and the weight loss clinic page explains how our free online consultation works.

If you are already leaning towards tirzepatide, the Mounjaro pen costs £169.99 per month at the 2.5mg starting dose, with every dose in stock. A new customer's first order is £40 off with code FIRST40, and each later order is £25 off the standard price (code DOSE25). Prices checked 10 October 2026.

03 · How they work

How semaglutide and tirzepatide differ in action

The core difference is the number of hormone receptors each medicine activates. Tirzepatide is the first treatment of its kind to activate 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.¹

Semaglutide is a single-action GLP-1 medicine. This dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide (Wegovy/Ozempic).¹ In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

Both are prescription-only, both are weekly injections, and both work alongside a reduced-calorie diet and increased physical activity rather than replacing them. Neither is a shortcut, and neither suits everyone. A prescriber decides which, if either, is right for you.

Mounjaro is made by Eli Lilly and comes as a pre-filled multi-dose pen (KwikPen) in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹

04 · Trial evidence

What the trials show for tirzepatide and semaglutide

In the first large head-to-head trial (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; which suits you depends on your health profile, tolerance and prescriber advice, not the headline number alone.¹⁵

In the STEP 1 trial, adults on semaglutide 2.4mg (Wegovy) lost on average 14.9% of body weight over 68 weeks, compared with 2.4% on placebo.⁹ STEP 1 and SURMOUNT-1 were separate trials with different participants, so their numbers should not be set side by side as a head-to-head result. Trial averages do not predict your own result.

In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their 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 These are trial averages, and individual results vary.²

None of these trials tested Ozempic for weight loss as a UK-licensed use. If you want a closer look at the two weight-loss medicines, read which is more effective and whether semaglutide or Mounjaro is better for weight loss.

05 · Side effects

Side effects and why some people stop

In STEP 1, gastrointestinal side effects were reported by 74.2% of people on semaglutide 2.4mg, compared with 47.9% on placebo.⁹ 7.0% stopped treatment because of side effects, compared with 3.1% on placebo.⁹ Those figures are for Wegovy-dose semaglutide, not Ozempic and not tirzepatide.

The trial data show side effects as one reason people stop.

A fair safety comparison between tirzepatide and semaglutide depends on the individual: your medical history, other medicines and how you tolerate each. Our guide on whether semaglutide or tirzepatide is safer goes through this in more detail.

If you notice a new or worrying symptom on any GLP-1 medicine, speak to your prescriber. For severe, persistent stomach pain, yellowing of the skin or eyes, swelling of the face or throat, or difficulty breathing, get medical help straight away. You can also report suspected side effects through the MHRA Yellow Card scheme.¹⁹

06 · Switching

Switching between semaglutide and tirzepatide

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

Never run two GLP-1 medicines together. That includes taking a leftover semaglutide pen while starting tirzepatide. 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.

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

If you are weighing up a change, our guide to choosing semaglutide or tirzepatide lists the questions to take to your prescriber.

07 · Other names

"Poor man's Ozempic" and other look-alike names

"Poor man's Ozempic" and "nature's Ozempic" are marketing phrases, not medicines. They usually point to low-cost supplements such as berberine. "Natural GLP-1" supplements are not medicines, are not regulated for this use and have no comparable trial evidence.

Licensed alternatives do exist, and they work differently. Orlistat is a tablet that blocks some dietary fat absorption and produces smaller average losses. Wegovy and Saxenda (liraglutide) are other licensed injectables. Saxenda is supplied at 6mg/ml and is a daily injection, unlike once-weekly Mounjaro and Wegovy.

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

Be wary of anyone offering to supply an injection without a consultation or prescription, however it is named. Prescription-only medicines should come from a pharmacy on the GPhC register.

08 · Getting a licensed option

Getting a licensed weight-loss medicine in the UK

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, and 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.

Privately, the route is straightforward. You complete a free online consultation and a GPhC-registered prescriber reviews it. Payment is taken when you place the order, and if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. Our registered pharmacy (GPhC 9012878) dispenses the order, with same-day dispatch when ordered by 3pm, and free next-day tracked delivery in discreet, temperature-controlled packaging.

Mounjaro is supplied directly through official LillyDirect supply, as genuine KwikPens, and ongoing monthly reviews are included.

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.

09 · Choosing between them

Which is better to use: semaglutide or tirzepatide?

In the head-to-head trial, average weight loss was larger on tirzepatide, but which suits you depends on you. SURMOUNT-5 is the first large trial that compares them directly, and it used semaglutide 2.4mg, the Wegovy dose.¹⁵ In that trial, more people on tirzepatide reached each weight-loss threshold than on semaglutide, and average loss was larger on tirzepatide.¹⁵

A larger average does not mean a larger result for every person. Tolerance, other medicines and medical history all matter. Some people do well on semaglutide and stay on it. Others move to tirzepatide after discussing it with a prescriber.

Our longer comparison, which is better, semaglutide or tirzepatide, walks through the factors; the choice is made with a prescriber, not from a headline figure.

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