Appetite Suppression: What It Is and How It Works (October 2026)

01 · The core answer

What is appetite suppression?

Appetite suppression is any process that reduces hunger or makes you feel full sooner. It can come from hormones, from food choices, from sleep and stress, or from medicines.

For weight management, the most relevant licensed route is a GLP-1 based medicine. Mounjaro is the brand name for tirzepatide, a once-weekly injectable prescription medicine made by Eli Lilly, licensed in the UK for weight management in adults and for type 2 diabetes.¹ In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

02 · Your decision

Is medical appetite suppression relevant to you?

It may be if you are an adult with a BMI of 30 or more, or 27 or more with a weight-related condition, and diet and activity alone have not been enough. A prescriber decides whether treatment is suitable for you.

NHS access exists but is being phased in over several years. NICE recommends Mounjaro for adults with a BMI of at least 35 plus at least one weight-related condition, and the primary-care rollout began in June 2025 with the highest-need groups first.⁴ Many people who meet the licensed criteria choose regulated private treatment rather than waiting.

If you want to explore that route, our weight loss clinic explains the process, and the Mounjaro pen page shows current prices, with all doses in stock. A new customer's first order is £40 off with code FIRST40.

03 · How Mounjaro works

How Mounjaro suppresses appetite

Mounjaro suppresses appetite through gut-hormone signalling. 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

This is hormone-based appetite suppression: it works with signals your body already uses to tell you that you are full. That is why people often describe feeling satisfied by smaller portions and thinking about food less between meals, which supports a reduced-calorie diet rather than replacing it.

The medicine is used alongside a reduced-calorie diet and increased physical activity, and individual results vary. It is injected under the skin on the same day each week, with or without food.¹³ Our guide on when you feel appetite suppression on Mounjaro goes into timing in more detail.

04 · When it starts

When appetite changes start

Appetite change on Mounjaro begins at different times for different people. The 2.5mg starting weeks are about adjustment, and some people notice appetite change and early loss in week one, while others feel little until a higher dose. Both are normal.

Everyone starts on 2.5mg once a week. This starting dose is about letting your body adjust, not about weight loss itself. After at least 4 weeks the dose increases to 5mg, then can step up by 2.5mg at a minimum of 4-week intervals up to a maximum of 15mg weekly, depending on response and tolerance.¹ Many people settle at 5mg, 10mg or 15mg; higher is not automatically better.

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in. Weight loss is gradual by design: think in months, not days.

If appetite suppression feels too strong or you struggle to eat enough, tell your prescriber. Tell your prescriber about any new or lasting symptom, and you can report suspected side effects through the MHRA Yellow Card scheme.¹⁹ 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 or eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing.

05 · Tablets and supplements

Appetite suppression tablets and supplements

There is no tablet form of Mounjaro; tirzepatide is injection-only in the UK. Two GLP-1 weight-loss tablets are now licensed in the UK: Wegovy tablets (oral semaglutide, made by Novo Nordisk) and Foundayo (orforglipron, made by Eli Lilly). They are different medicines from Mounjaro, with their own dosing, eligibility checks and trial results, and both are prescription-only.²⁰²¹

Orlistat is a tablet that blocks some dietary fat absorption and produces smaller average losses.

"Natural GLP-1" supplements, such as berberine, are not medicines, are not regulated for this use and have no comparable trial evidence. They are low-cost supplements with no clinical oversight, and their dosing is not standardised. Nicknames such as "poor man's Ozempic" are marketing, not a medical category. Dramatic weight-loss claims attached to them should be treated with caution.

Be especially wary of anything promising faster results outside a licensed pathway. Mounjaro must not be combined with other GLP-1 medicines, 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.⁷

06 · Other medicines and causes

Other medicines and causes of reduced appetite

Many things can lower appetite besides weight-loss medicines, and they are not interchangeable with them. Medicines prescribed for other conditions, stress and raised cortisol, illness, and changes in sleep can all alter how hungry you feel.

If you take a medicine for another condition and have noticed a change in appetite, ask the prescriber who manages it. Do not stop or change it yourself. We cover some common questions separately, including ADHD medicines and appetite, Concerta and Ritalin versus Adderall.

A sudden, unexplained loss of appetite is a reason to speak to a GP, whatever the cause. It is not something to treat with a supplement.

07 · Non-drug tips

Appetite suppression tips without medicine

Lifestyle tactics can nudge hunger, but they are far weaker than the licensed medicines. Regular meals with protein and fibre, enough sleep, managing stress and staying hydrated all help some people feel more settled between meals.

Caffeine is a common habit-based approach; see our page on caffeine and appetite suppression. Treat these as low-risk extras at best, not substitutes for medical treatment.

Exercise is worth keeping regardless. Mounjaro is licensed for use alongside a reduced-calorie diet and increased physical activity, so movement supports treatment rather than competing with it.

08 · Tirzepatide vs semaglutide

Tirzepatide versus semaglutide on appetite

Mounjaro and Wegovy are both licensed GLP-1 based treatments, but only tirzepatide also activates GIP. 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.

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 Trial averages do not predict your own result. Read our comparison of tirzepatide and semaglutide appetite suppression for more.

Ozempic is semaglutide licensed for type 2 diabetes. It is not a UK weight-loss medicine, and a regulated UK pharmacy will not supply it for weight loss.¹

09 · Getting a prescription

Getting appetite suppression on prescription

Licensed appetite-suppressing medicines are prescription-only, so the route starts with a consultation. Our guide to prescription appetite suppression explains the options in more depth.

With us, the free online consultation is a short health questionnaire reviewed by a GPhC-registered prescriber. 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 GPhC-registered (9012878) and supply Mounjaro through official LillyDirect supply, directly from Eli Lilly's UK distribution. Delivery is free, next-day and tracked in temperature-controlled packaging, with same-day dispatch when ordered by 3pm.

Ongoing monthly reviews are included, so your prescriber can guide your dose. Every future order is £25 off the standard price (code DOSE25).