What Is GLP-1? A UK Guide to GLP-1 Medicines (October 2026)

01 · The core answer

Is a GLP-1 medicine relevant to you?

A GLP-1 medicine is relevant if you are an adult looking at medically supported weight management and you meet the licensed criteria. Mounjaro is licensed in the UK for weight management in adults, used alongside a reduced-calorie diet and increased physical activity.¹ Individual results vary.

Mounjaro is the brand name for tirzepatide, a once-weekly injectable prescription medicine made by Eli Lilly. It is not simply "GLP-1": it is a dual-action treatment, which is the main difference from single-action GLP-1 medicines such as semaglutide.¹

02 · Next step

What to do next

Start by reading how the treatment is supplied and reviewed. Our weight loss clinic explains the full pathway, and the Mounjaro pen page shows current prices and the free online consultation. Every order is reviewed by a GPhC-registered prescriber, and unsuitable orders are refunded automatically.

If you are unsure whether the whole category is trustworthy, our guide asking whether GLP-1 is a con goes through the common doubts honestly.

03 · How GLP-1 works

How GLP-1 works in the body

Your gut releases GLP-1 after you eat. It tells the brain you are getting full, slows stomach emptying and helps insulin work properly.

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

For more on the science, see our explainer on GLP-1 technology and the research trail in Mounjaro on Google Scholar.

04 · Which GLP-1 is best

Is there a best GLP-1 for weight loss?

There is no single best GLP-1 for everyone; the right choice depends on your health, your tolerance and your prescriber's judgement.

Wegovy (semaglutide) is another licensed option; you can read about the Wegovy pen separately.

05 · Natural GLP-1 myths

Can you get GLP-1 naturally?

Your body already makes GLP-1 naturally, but foods, teas and supplements are not a substitute for a licensed medicine. Eating a balanced diet with plenty of protein and fibre supports healthy appetite signals, and that is a sensible habit with or without treatment.

Where marketing goes further, be sceptical. Products sold as "nature's Ozempic" are low-cost supplements with no clinical oversight, and dosing is not standardised. Ozempic itself is semaglutide licensed for type 2 diabetes — it is not a UK weight-loss medicine. Dramatic weight-loss claims on these products are not backed by the trial evidence behind Mounjaro or Wegovy.

Gut-health products such as a GLP-1 prebiotic are explained in their own guide. There is no "best" GLP-1 tea, snack or food list; a regular, balanced diet is the practical advice.

06 · Who should be careful

Who should not take GLP-1 drugs?

Whether a GLP-1 medicine is safe for you is decided by a prescriber after reviewing your medical history, current medicines and plans such as pregnancy. The patient information leaflet lists who should not use Mounjaro, so read it before starting.¹³ You should not take Mounjaro if you are allergic to tirzepatide or any of its ingredients, and it should not be used during pregnancy or while trying to conceive. Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems. Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. If you become pregnant during treatment, stop the medicine and tell your prescriber promptly. Mounjaro slows stomach emptying, which can reduce how well oral contraceptive pills are absorbed: switch to a non-oral method, or add a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.

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. If you notice any other new symptom while treated, tell your prescriber and report it through the Yellow Card scheme.¹⁹ Sticking with treatment matters too; our guide to GLP-1 adherence covers how people stay on track.

07 · NHS access

NHS access to GLP-1 treatment

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.