GLP-1 Users: What to Eat, Take and Know (October 2026)

01 · The meaning

Who are GLP-1 users, and is this you?

A GLP-1 user is someone prescribed a medicine that acts on the GLP-1 hormone pathway, which helps regulate appetite and blood sugar. Medicines in this group include semaglutide, sold as Wegovy, and liraglutide, sold as Saxenda and similar products. Tirzepatide, sold as Mounjaro, goes a step further.

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 So is GLP-1 the same as Mounjaro? Not exactly. Mounjaro is one brand within the wider group, and its dual action is what distinguishes it from single-action medicines such as semaglutide.

Users fall into two broad groups: adults using treatment for weight management, and adults with type 2 diabetes. In the UK, Mounjaro is licensed for both. What matters for you is whether the guidance fits your situation, and that is a conversation with a prescriber.

If you are weighing up options, our weight loss clinic page explains how the treatments compare and how a consultation works.

02 · Your next step

What should a GLP-1 user do next?

Start with the basics before buying anything: protein, fluids, movement and sleep. Products come last. Mounjaro is licensed alongside a reduced-calorie diet and increased physical activity, so the lifestyle layer is part of the treatment, not an extra.¹

If you meet the licensed criteria, you can start a free online consultation, reviewed by a GPhC-registered prescriber. Your first 2.5mg Mounjaro pen costs £129.99 with code FIRST40 (standard price £169.99). Prices checked 11 October 2026.

03 · Diet and food

Diet and foods for GLP-1 users

No food is banned on Mounjaro, including bananas, but some choices make treatment easier and more effective. Prioritise protein at each meal, vegetables and fibre, and regular fluids.

Many people feel worse after very fatty, fried or very sugary food, and large portions sit heavily because the stomach empties more slowly. Smaller, slower meals work better. Treatment is licensed alongside a reduced-calorie diet, so the aim is a sustainable deficit, not a perfect food list.

A practical pattern looks like this:

• Protein first: eggs, fish, poultry, lean cuts of meat, yoghurt, tofu, beans and lentils.
• Vegetables and fibre: they add volume without many calories and support regular bowels.
• Smaller portions: stop when comfortably full, because fullness arrives sooner.
• Limit: deep-fried dishes, very rich sauces and sugary snacks if you find they make you feel unwell.

Our guide to the diet for Mounjaro users goes further into meal structure.

Recipes for GLP-1 users

You do not need special recipes. Look for simple meals built around a protein source, a vegetable and a modest portion of carbohydrate: a veg-heavy omelette, grilled fish with greens, a lentil soup, or a chicken and vegetable traybake. Bake, grill, steam or poach instead of deep-frying. Batch cooking helps on injection days when appetite or energy dips.

Alcohol and coffee

There is no direct interaction between Mounjaro and alcohol, but drinking on a reduced appetite and emptier stomach can hit harder than usual, and alcohol adds calories that work against your goals. If you also take insulin or a sulfonylurea, alcohol increases the risk of low blood sugar.¹

There is no interaction between Mounjaro and caffeine, so coffee and tea are fine. Strong coffee on an empty, slower-emptying stomach can aggravate nausea or reflux for some people, and high-calorie coffee drinks are an easy place for the calorie deficit to leak. Coffee rules circulating on social media have no clinical basis.

04 · Protein and drinks

Protein and protein drinks for GLP-1 users

Protein matters because some of any rapid weight loss comes from lean tissue, and protecting muscle protects your metabolism, strength and appearance. The two levers are adequate protein and resistance exercise two or more times a week.¹

The practical rule is to include a protein source at every meal, which is harder when appetite is low. This matters more, not less, as the dose rises and appetite falls.

Ask your prescriber or a dietitian what suits your size, activity and health.

Are protein shakes worth it?

A protein shake can be a convenient option on days when solid food feels unappealing. Check the label for added sugar and avoid very rich, creamy blends if fatty food sits badly with you. Sip slowly rather than drinking quickly, since large volumes can feel heavy. Our comparison of protein shakes for GLP-1 covers what to look for.

Protein bars, yoghurts, cottage cheese and milk are alternatives. None is required, and a shake is a convenience rather than a medical need.

Resistance exercise

Increased physical activity is part of the licence, not an optional extra. The evidence-backed pattern is regular moderate activity, such as brisk walking, plus resistance work for muscle. Start where you are and build; on injection days with early side effects, lighter movement still counts. Exercise also protects against regain if you later stop treatment.¹

05 · Supplements and vitamins

Supplements, vitamins, collagen and electrolytes

No supplement is required with Mounjaro, but eating much less can leave gaps, so a standard daily multivitamin is a reasonable safety net while losing weight. Discuss anything beyond that with a pharmacist.¹

Oral supplements, like other oral products, may be absorbed more slowly when you start treatment. That is one reason to keep your routine simple and avoid stacking products.

If you want detail on specific products, see our guides to vitamins for GLP-1, multivitamins for GLP-1 users and multivitamins for GLP-1 support.

Natural GLP-1 boosters

Supplements sold as natural GLP-1 boosters are not equivalents and are not substitutes for prescribed treatment. They are low-cost supplements with no clinical oversight, and dosing is not standardised. Treat dramatic weight-loss claims on their packaging with scepticism.

Collagen, electrolytes and probiotics

Collagen powders and electrolyte mixes are not required with Mounjaro. If you are tempted, ask a pharmacist about ingredients, particularly if you have kidney, heart or blood-pressure conditions. For electrolytes, the basics still apply: water within reach through the day, and food that includes salt, fruit and vegetables.

Gut-health products are a similar story. Our piece on the GLP-1 probiotic for weight loss covers gut-health products, and our note on prenatal vitamins and GLP-1 is worth reading if you are planning a pregnancy. 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.

06 · Hydration

Hydration for GLP-1 users

Drinking enough matters more on Mounjaro than usual. Reduced appetite means less fluid from food, and vomiting or diarrhoea can dehydrate you quickly, which is the main route to the rare kidney problems reported with this class.¹

Keep water within reach through the day. Treat inability to keep fluids down as a contact-your-clinical-team issue, not something to push through.

Practical habits help: a bottle you refill, herbal tea, diluted squash without added sugar, and soups. If plain water feels unpleasant, sip small amounts often rather than drinking large volumes at once.

07 · Downsides and risks

The downsides, and who cannot take GLP-1

The main downside of treatment is that it can make you feel unwell, particularly after meals that are large, fatty or sugary. Side effects tend to be most noticeable around starting and dose increases, and the full list is in the patient information leaflet.¹³

Other downsides are practical: the medicine is a long-term commitment for many people, it needs diet and activity alongside it, and it can reduce absorption of oral contraceptives because stomach emptying slows. 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 If you take insulin or a sulfonylurea, doses may need adjusting because of low blood sugar risk.

Who cannot take it? 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. Always share your full medical history and medicine list during consultation. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

If you notice any new symptom, talk to your prescriber and report it through the Yellow Card scheme.¹⁹ A related read is GLP-1 users may face a hidden health problem.

08 · Results and stopping

What to expect, and what happens if you stop

When you start, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹ Weight change builds gradually as the dose rises, and trial results were measured over the full trial period.

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. These are trial averages; individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

Stopping: 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 Can you come off without regaining? In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued treatment lost a further 5.5% on average. Stopping should always be planned with your prescriber, with diet and activity habits ready to carry the load.

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

10 · NHS or private

NHS or private access for GLP-1 users

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.

NHS access to Wegovy runs through specialist weight-management services; ask your GP. If you choose private treatment, we are a GPhC-registered pharmacy (9012878), with Mounjaro supplied via official LillyDirect supply, free next-day tracked delivery in temperature-controlled packaging and ongoing monthly reviews included. You can also track your progress with our free GLPTrackr app. Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. Individual results vary, and this page is information, not a substitute for medical advice.