GLP-1 Types Explained: Which Kind Is Mounjaro? (October 2026)

01 · The short answer

The main types of GLP-1 medicine

The clearest way to sort GLP-1 medicines is by what they act on. Single-action medicines target the GLP-1 receptor only. Dual-action tirzepatide, sold as Mounjaro, activates both GIP and GLP-1 receptors.¹ That dual action is what separates Mounjaro from single-action GLP-1 medicines such as semaglutide (Wegovy and Ozempic).¹

Each medicine is a licensed treatment with its own evidence base, and your prescriber chooses between them based on your health, goals and tolerance.

02 · Your decision

Which type is relevant to you?

Rather than asking which GLP-1 is best, it helps to ask which one is licensed for your situation. If you are an adult living with excess weight and want a once-weekly option, Mounjaro and Wegovy are the two weekly pens most people compare. If you live with type 2 diabetes, your diabetes team decides the choice within NHS pathways. If you have type 1 diabetes, none of this is a do-it-yourself decision, and our guide to GLP-1 for type 1 diabetes explains why.

If you are ready to see whether private treatment suits you, you can check the Mounjaro pen and its prices. The 2.5mg starter pen is £169.99 at standard price, and your first 2.5mg pen costs £129.99 with code FIRST40. Every strength is in stock, prices checked 10 October 2026. The consultation is free and reviewed by a GPhC-registered prescriber; payment is taken when you place the order, and if the prescriber decides treatment is not suitable, the order is refunded automatically in full.

03 · How GLP-1 medicines work

How GLP-1 medicines work

GLP-1 is a natural gut hormone, and GLP-1 medicines are designed to act on the same receptor. Together with GIP, these gut-hormone signals 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.¹

You may see these medicines called GLP-1 agonists or GLP-1 receptor agonists. "Agonist" simply means the medicine activates a receptor. Tirzepatide is sometimes described as a dual agonist because it activates both GIP and GLP-1 receptors. GLP-1 is a natural gut hormone, and these medicines mimic its action rather than being a stimulant or a fat burner.

Slowed stomach emptying is the reason absorption of some other oral medicines can change. Differences between types show up mainly in dosing schedule, licensed use and the trial evidence behind each product.

04 · What type of GLP-1 is Mounjaro?

What type of GLP-1 is Mounjaro?

Mounjaro is a dual GIP and GLP-1 medicine. Strictly, tirzepatide is not a "pure" GLP-1 agonist, though it is usually grouped with the GLP-1 family because it acts on the GLP-1 receptor too.¹ It is a once-weekly prescription injection made by Eli Lilly and supplied as a pre-filled multi-dose pen (KwikPen) in strengths from 2.5mg to 15mg.¹

In the UK it is licensed for weight management in adults and for type 2 diabetes.¹ It is used alongside a reduced-calorie diet and increased physical activity. In the SURMOUNT-1 trial, 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.

For a worked example, someone starting at 100 kg and matching the 15mg average of 20.9% would lose about 21 kg. That is arithmetic on a trial average, not a prediction for any one person.

Our page on the Mounjaro type of medication goes deeper on how the pen works day to day, and the patient information leaflet is the definitive guide to using it.¹³

05 · Type 1 diabetes and GLP-1

Type 1 diabetes and GLP-1 medicines

Mounjaro's UK licence covers weight management and type 2 diabetes, and type 1 diabetes is not among its licensed uses.¹

What matters practically is that type 1 diabetes is managed by a specialist diabetes team, with insulin doses carefully balanced. If you take insulin, doses may need adjusting to avoid low blood sugar, so your diabetes team needs to be involved in any decision.¹

If you live with type 1 diabetes and are curious, speak to your diabetes team first and do not order a weight-loss pen on your own. For longer reading, see our pages on Mounjaro and type 1 diabetes, whether a type 1 can take Mounjaro and using GLP-1 in type 1 diabetes.

06 · Type 2 diabetes vs weight loss

Type 2 diabetes versus weight management

GLP-1 medicines are used in two overlapping settings: managing type 2 diabetes and managing weight. Mounjaro is licensed for both in the UK.¹ Others are marketed with a particular emphasis. Ozempic and Wegovy, for instance, share the active ingredient semaglutide but are presented as separate products with their own dose schedules and licensing, so always check which product a prescriber means.

Is Ozempic or Wegovy the better choice? 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 and Wegovy. Ozempic or Mounjaro for type 2 diabetes? A head-to-head diabetes trial exists (SURPASS-2),³ but the right answer for you depends on your blood sugar control, other conditions, tolerance and NHS guidance, and belongs to your diabetes team.⁸

We cover this in more depth in our guide to GLP-1 and type 2 diabetes.

07 · Daily, weekly and tablet forms

Daily, weekly and tablet forms

Dosing schedule is the most practical difference between types. Liraglutide (supplied at 6mg per millilitre in products such as Saxenda) is a daily injection, unlike once-weekly Mounjaro and Wegovy. A weekly pen means fewer injections, which many people find easier to keep up.

Wegovy's dose ladder runs 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg. Doses step up after 4 weeks on each of 0.25mg, 0.5mg, 1mg and 1.7mg, so the 2.4mg maintenance dose starts from week 17, and 2.4mg is the licensed maintenance dose for weight management.¹⁸ Mounjaro uses its own ladder of strengths from 2.5mg to 15mg, stepped up gradually under prescriber review.¹

Tablet forms of GLP-1 medicines have also arrived, each with its own product information. If you are curious about a particular product, the Wegovy pen page and our product pages show current options and prices.

08 · Avoid unregulated lookalikes

Supplements and "poor man's Ozempic"

The phrase "poor man's Ozempic" usually refers to supplements such as berberine marketed as natural alternatives. These are low-cost supplements with no clinical oversight, and they are not GLP-1 medicines. Dosing is not standardised, and dramatic weight-loss claims attached to them should be treated with scepticism. They are not an established substitute for a licensed prescription treatment.

A more serious risk is counterfeit or unlicensed injectable products sold online. The MHRA publishes counterfeit medicine alerts and runs the Yellow Card scheme for reporting suspected problems.⁷ Be wary of any seller offering to supply a GLP-1 pen without a consultation or prescription, or promising specific results. You can check any UK pharmacy on the GPhC register; ours is GPhC 9012878. Our Mounjaro is supplied through official LillyDirect supply, direct from Eli Lilly's UK distribution.

09 · What to avoid on Mounjaro

What to avoid while taking Mounjaro

The main thing to avoid is not telling your prescriber about everything else you take. Because Mounjaro slows stomach emptying, it can affect how quickly some oral medicines are absorbed, particularly when you start treatment or increase the dose.¹ Mention warfarin or other narrow-margin medicines, insulin, and sulfonylureas, where doses may need reducing to avoid low blood sugar. No adjustment is needed for paracetamol.¹

The medicine can also reduce absorption of oral contraceptives because stomach emptying slows.⁷ The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ Do not use leftover or borrowed pens, and do not buy from sellers who skip the consultation. If you notice a new symptom, tell your prescriber and report suspected side effects through the Yellow Card scheme.¹⁹ 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 or eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing.

Pens are stored in the fridge at 2–8°C and must never be frozen; once in use, a KwikPen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away. Do not use a pen that has been above 30°C or frozen. Treatment is not a substitute for a reduced-calorie diet and more physical activity: it works alongside them.

10 · NHS and private access

NHS and private 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, 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).⁴ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.⁶ NHS access to Wegovy runs through specialist weight-management services; ask your GP.

Private treatment still means a proper clinical process: a free online consultation, review by a GPhC-registered prescriber, and ongoing monthly reviews, with free next-day tracked delivery in temperature-controlled packaging. Our weight loss clinic explains the full journey. Mounjaro is a prescription-only medicine, used alongside diet and activity, and individual results vary.¹