Mounjaro Class: What Type of Drug Is Tirzepatide? (October 2026)

01 · The short answer

What class is Mounjaro?

Mounjaro is a dual GIP and GLP-1 receptor agonist. Its active ingredient, tirzepatide, is made by Eli Lilly and given as a once-weekly injection from a pre-filled KwikPen.¹ In everyday language, people often group it with the 'GLP-1 medicines' or 'weight-loss jabs'. That label is fair, but it hides the detail that matters most: tirzepatide does something the older GLP-1-only medicines do not.

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 If you want the wider family tree, our guides to the drug class explained and the GLP-1 class of drugs go further.

02 · What to do next

Does the class matter for you?

The class matters if you are comparing treatments. It matters much less than your own health history, because a prescriber chooses a medicine for the person, not the label. Mounjaro is supplied only after an online consultation reviewed by a GPhC-registered prescriber, and it is used alongside a reduced-calorie diet and increased physical activity.¹

If you are ready to look at treatment, the Mounjaro pen page shows current prices; the 2.5mg starting pen is £169.99 at the standard price, and the free consultation is how you find out whether it is suitable. Prices checked 10 October 2026. Our weight loss clinic page covers the wider service.

Related guide: Mounjaro scurvy.

Related guides: Mounjaro class of medication and Mounjaro and pmdd.

03 · How the dual action works

How dual GIP and GLP-1 action works

Tirzepatide mimics two natural gut hormones, GIP and GLP-1. Tirzepatide is the first treatment of its kind to activate two natural gut-hormone receptors at once: GIP and GLP-1.¹

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

The class also explains why the medicine is licensed for both weight management and type 2 diabetes. The same hormone pathways influence appetite, stomach emptying and insulin response. The patient information leaflet lists the full set of side effects and warnings, and you should read it before starting.¹³

04 · Mounjaro vs other GLP-1 drugs

Mounjaro compared with Wegovy, Ozempic and Saxenda

Mounjaro is the dual-action option; the others act on GLP-1 alone.

Liraglutide is a daily injection, unlike once-weekly Mounjaro and Wegovy. Ozempic and Wegovy share the same active ingredient, but they are different products with different licences and dose ranges. If you want to see the two weekly pens side by side, our Wegovy pen page has the details.

SURMOUNT-5 was the first large head-to-head trial of tirzepatide and semaglutide, and results from separate trials should not be set side by side as if they were head to head.¹⁵ Whichever medicine you choose, a prescriber should confirm it suits you.

05 · What the trial evidence shows

What the trial evidence shows for this class

The dual-action class has been tested in large trials, and the headline result comes from SURMOUNT-1. 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 — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.² A trial average describes a group, so it does not predict your own result.

Class membership alone does not tell you how well a medicine performs. Each medicine has to be judged on its own trial evidence.

06 · Supplements and 'natural' alternatives

The 'poor man's Ozempic' and 'natural Ozempic' claims

Products marketed as a 'poor man's Ozempic' or 'nature's Ozempic' are not in the GLP-1 class. Berberine is the usual example. These are low-cost supplements with no clinical oversight, available cheaply without assessment, and dosing is not standardised.

Sellers use the Ozempic name because it is well known, not because the supplement acts on the same receptors. A licensed medicine goes through a prescriber review; a supplement does not.

Be equally careful with anyone offering injectable tirzepatide or semaglutide without a consultation or prescription. The MHRA publishes counterfeit medicine alerts, and you can report suspect products or side effects through the Yellow Card scheme.⁷¹⁹

07 · Getting it through the NHS

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, 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. Your GP can tell you where you sit in your local rollout.

08 · Clearing the system and stopping

How long it stays in the body

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.¹ There is no way to speed this up, and nothing needs doing while it clears.¹

This is a property of this particular medicine rather than a feature of the whole class, so do not assume the same timing applies to other GLP-1 products. Speak to your prescriber before stopping, and about any other medicines you take.

09 · 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