GLP-1 Medications: 50 Common Questions Answered

GLP-1 medicines are prescription-only treatments that reduce appetite and help control blood glucose. In the UK, Wegovy (semaglutide), Mounjaro (tirzepatide), liraglutide (Saxenda and others) and, since 2026, two GLP-1 tablets are licensed for weight management in adults who meet BMI criteria, used alongside diet and activity. They can produce substantial weight loss for many people, but side effects are common, they are not suitable for everyone and weight is often regained after stopping. Below are clear, evidence-based answers to 50 of the most common questions. For decisions about your own treatment, always speak to a prescriber.

The basics

1. What does GLP-1 mean?

GLP-1 stands for glucagon-like peptide-1, a hormone released by the gut after eating. It signals fullness to the brain, slows stomach emptying, boosts insulin when glucose is high and reduces glucagon. GLP-1 medicines mimic it but last much longer. Our plain-English guide to GLP-1 medications explains more.

2. How do GLP-1 medicines cause weight loss?

Mainly by acting on appetite centres in the brain, so you feel full sooner, feel less hungry between meals and often think about food less. Slower stomach emptying adds to fullness. Weight loss follows from eating less over time. They do not burn or dissolve fat directly.

3. Is Mounjaro a GLP-1?

Mounjaro (tirzepatide) acts on GLP-1 receptors and on GIP receptors, so it is a dual GIP/GLP-1 receptor agonist. It is usually grouped with GLP-1 medicines because it works similarly and has similar side effects. See how Mounjaro works.

4. What is the difference between Ozempic and Wegovy?

Both contain semaglutide, but Ozempic is licensed for type 2 diabetes and Wegovy for weight management, at different doses and in different pens. They are not interchangeable products. See Ozempic vs Wegovy.

5. Which GLP-1 medicines are licensed for weight loss in the UK?

At the time of writing: Wegovy injections, Mounjaro, liraglutide products such as Saxenda, Wegovy tablets (MHRA approval June 2026) and Foundayo (orforglipron, MHRA approval August 2026). Our overview of every UK weight loss medication also covers orlistat and others.

6. Are there GLP-1 tablets?

Yes. Rybelsus has been licensed for type 2 diabetes for several years. For weight management, oral semaglutide (Wegovy tablets) and orforglipron (Foundayo) were approved in 2026. Oral semaglutide must be taken on an empty stomach with a sip of water; orforglipron can be taken with or without food. See our oral GLP-1 guide.

7. How long have GLP-1 medicines been around?

The first GLP-1 medicine for type 2 diabetes was approved in Europe in 2006. Liraglutide for weight management followed, and Wegovy was authorised by the MHRA in 2021. Mounjaro was authorised for weight management in the UK in 2023.

Eligibility and access

8. Who can be prescribed a GLP-1 medicine for weight loss?

Licences generally cover adults with a BMI of 30 or more, or 27 or more with a weight-related condition such as high blood pressure, type 2 diabetes or sleep apnoea, alongside diet and activity. See who can get weight loss injections.

9. Are the BMI thresholds different for different ethnic groups?

NICE recommends lower BMI thresholds, usually by 2.5 kg/m², for people from South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean backgrounds, who tend to develop weight-related conditions at lower BMIs. See BMI thresholds and ethnicity.

10. Can I get Mounjaro on the NHS?

NICE TA1026 recommends tirzepatide, with a phased rollout in NHS primary care that began in June 2025 for people with a BMI of at least 40 and at least four of five specified conditions. Wider access is planned over several years. See Mounjaro on the NHS.

11. Can I get Wegovy on the NHS?

NICE TA875 recommends Wegovy within specialist weight management services for up to two years, for adults meeting BMI and comorbidity criteria. Access depends on local services. See Wegovy on the NHS.

12. Can I get a GLP-1 medicine privately?

Yes, through regulated online pharmacies, online doctor services and clinics, after a consultation. A responsible provider will verify your identity and weight and review your medical history. See private vs NHS weight loss treatment and our provider comparison.

13. Why do online providers ask for photos or ID?

To confirm who you are and that your weight meets licence criteria, reducing the risk of inappropriate prescribing. Regulators expect these checks for weight loss medicines. See why online pharmacies verify ID and weight.

14. What affects the cost of private treatment?

The medicine, the dose, the provider's service model, whether consultations and follow-up are included, and delivery. Higher doses of some medicines cost more. We do not list prices in our guides; see our price comparison for what affects cost.

15. Can I get a GLP-1 medicine without a prescription?

No. All GLP-1 medicines are prescription-only in the UK. Products offered without a prescription, through social media, salons or unregulated websites, may be fake or contaminated. See fake weight loss jabs.

Taking the medicine

16. How are the injections given?

Wegovy and Mounjaro are injected once a week under the skin of the abdomen, thigh or upper arm, using a pre-filled pen. Liraglutide is injected daily. Your prescriber or pharmacist should explain the technique. See how to use the Mounjaro KwikPen and the Wegovy pen.

17. Do the injections hurt?

The needles are very fine and most people find the injections cause little discomfort. Some notice mild redness, itching or a small lump at the site. Rotating sites helps.

18. Why does the dose start low?

Starting low and increasing gradually, usually every four weeks for weekly injections, helps the body adjust and reduces gastrointestinal side effects. See Mounjaro doses and Wegovy doses.

19. Do I have to reach the highest dose?

No. The right dose balances benefit and side effects for you. Some people stay on a lower dose that works well. Your prescriber decides, in line with the SmPC.

20. What if I miss a dose?

The SmPC for each medicine sets out what to do, depending on how long it has been. Missing several doses may mean restarting at a lower dose. See Mounjaro missed dose and ask your prescriber.

21. How should I store my pens?

Unused pens are generally kept in a fridge, not frozen. Once in use, some can be kept at room temperature for a limited time, as stated in the patient leaflet. See storing and travelling with Mounjaro.

22. How do I take the Wegovy tablet?

According to the UK approval, once daily on an empty stomach with only a sip of water, then waiting 30 minutes before eating, drinking or taking other tablets. Check the patient leaflet for exact instructions. See oral semaglutide.

Results

23. How much weight could I lose?

Trial averages were around 15% with semaglutide 2.4mg (STEP 1) and around 20% with the highest tirzepatide dose (SURMOUNT-1), over about a year and a half. Individual results vary widely, and nobody can promise a specific outcome. See realistic weight loss expectations.

24. How quickly will I notice a difference?

Appetite changes are often noticed in the first weeks. Weight loss usually builds gradually over months as the dose increases, and tends to level off after around a year or more.

25. Is Mounjaro more effective than Wegovy?

In the head-to-head SURMOUNT-5 trial, tirzepatide produced greater average weight loss than semaglutide 2.4mg. But individual responses vary, and side effects, preferences and health conditions also matter. See Mounjaro vs Wegovy.

26. What if I am not losing weight?

Some people respond less than others. Your prescriber may review the dose, your diet and activity, other medicines and conditions, or consider another approach. See what if GLP-1 treatment doesn't work.

27. Why has my weight loss stopped?

Weight loss naturally slows and plateaus as the body reaches a new balance. This is expected. See weight loss plateaus.

28. Do GLP-1 medicines have benefits beyond weight?

Yes, in specific groups. The SELECT trial found semaglutide reduced major cardiovascular events in people with obesity and established heart disease. SURMOUNT-OSA found tirzepatide reduced sleep apnoea severity. They also lower blood glucose. See tirzepatide and sleep apnoea.

Side effects

29. What are the most common side effects?

Nausea, diarrhoea, constipation, vomiting, indigestion, burping and abdominal discomfort, mostly mild to moderate and most common after starting and dose increases. See Mounjaro side effects and Wegovy side effects.

30. How can I reduce nausea?

Eat smaller meals slowly, stop when full, avoid rich, fatty or spicy food, and keep hydrated. Tell your prescriber if it persists. See managing nausea.

31. What are the serious side effects?

Uncommon but serious effects include pancreatitis, gallbladder problems, dehydration leading to kidney problems, and allergic reactions. People with diabetes on insulin or sulfonylureas have a higher risk of hypoglycaemia. See pancreatitis risk and gallbladder problems.

32. Will I lose muscle?

Some weight lost is lean tissue, including muscle, as with any substantial weight loss. Eating enough protein and doing strength exercise help protect it. See preserving muscle.

33. Can GLP-1 medicines cause hair loss?

Hair thinning can occur during rapid weight loss, usually as temporary shedding a few months in. It often recovers. See Mounjaro and hair loss.

34. What is "Ozempic face"?

A popular term for facial changes from losing fat in the face, which can happen with substantial weight loss by any method. See facial changes and loose skin.

35. Do GLP-1 medicines affect mood?

Regulators have reviewed reports of mood changes and suicidal thoughts. In 2024 the European Medicines Agency's safety committee concluded the evidence did not support a causal link, and monitoring continues. Tell your prescriber about any mental health history or changes. See GLP-1 medication and mental health.

Safety and other medicines

36. Who should not take GLP-1 medicines?

People who are pregnant, trying to conceive or breastfeeding; those with a personal or family history of medullary thyroid carcinoma or MEN2 (as noted in the product information); and people with some other conditions, such as previous pancreatitis, need special caution or should avoid them. See who should not take GLP-1s.

37. Does Mounjaro affect the contraceptive pill?

Tirzepatide may reduce the effectiveness of oral contraceptives. The MHRA advises a non-oral method, or adding a barrier method, for four weeks after starting and after each dose increase. See GLP-1s and contraception.

38. Can I take a GLP-1 medicine if I am planning a pregnancy?

GLP-1 medicines should be stopped before trying to conceive, with the length of the gap depending on the medicine as set out in the SmPC. Discuss timing with your prescriber. See pregnancy and fertility.

39. Do GLP-1 medicines interact with other medicines?

They can affect absorption of some oral medicines by slowing stomach emptying, increase hypoglycaemia risk with insulin or sulfonylureas, and may need extra monitoring with warfarin. Always share your full medication list. See GLP-1 medication interactions.

40. Can I drink alcohol?

Alcohol is not a listed direct interaction, but it can worsen nausea and reflux, add calories and contribute to dehydration and, in some people, low blood sugar. Heavy drinking raises pancreatitis risk. See Mounjaro and alcohol.

41. Do I need to stop before surgery?

Current UK multi-society guidance from 2025 generally advises continuing, with the anaesthetic team assessing aspiration risk, because these medicines slow stomach emptying. Always tell your surgical team and follow their instructions. See GLP-1 medication before surgery.

42. Can older people take GLP-1 medicines?

UK licences for Mounjaro and Wegovy have no upper age limit for adults. Older people need careful assessment for muscle loss, dehydration, kidney function and other medicines. See GLP-1 medication for people over 65.

43. Can I take a GLP-1 medicine if I have type 2 diabetes?

Yes. Several GLP-1 medicines are licensed for type 2 diabetes, and the weight management medicines can be used by people with diabetes. Other diabetes medicines may need adjusting. See GLP-1 medication and type 2 diabetes.

Diet and lifestyle

44. What should I eat on a GLP-1 medicine?

Smaller, balanced meals with protein at each meal, plenty of vegetables, fruit, wholegrains and fluids. Rich or fatty foods often worsen side effects. See what to eat on GLP-1 medication.

45. How much protein do I need?

Needs vary with body size, age and activity. Including a good protein source at every meal is a practical starting point; a dietitian can give individual advice. See protein on GLP-1 treatment.

46. Do I need to exercise?

Physical activity is part of every UK licence for these medicines. Strength training at least twice a week, plus regular moderate activity, helps protect muscle and bone. See exercise on GLP-1 medication.

47. Should I take vitamins or supplements?

Not everyone needs them. Eating less can make some nutrients harder to get, and the NHS advises many adults in the UK to consider vitamin D in autumn and winter. See vitamins and supplements.

Long term and stopping

48. How long will I need to take a GLP-1 medicine?

There is no fixed answer. NHS treatment with Wegovy under NICE TA875 is limited to two years. Many people regain weight after stopping, so some clinicians consider longer-term treatment for some people. Discuss a long-term plan with your prescriber. See long-term GLP-1 use.

49. What happens when I stop?

Appetite usually returns and many people regain a substantial amount of weight over the following year, on average. Health markers such as blood pressure may also drift back. See weight regain after stopping and Mounjaro maintenance.

50. Can I switch between GLP-1 medicines?

Yes, under a prescriber's guidance. Switching between products, such as from Wegovy to Mounjaro or from an injection to a tablet, needs a plan for timing and starting dose. Never take two GLP-1 medicines at the same time. See switching from Wegovy to Mounjaro and switching from an injection to a tablet.

Quick reference: UK GLP-1 weight management medicines

Licences and NHS availability change. Check the SmPC on medicines.org.uk, the MHRA and NICE for the latest information.

Questions to ask at your consultation

Whether you see your GP, an NHS specialist service or a private prescriber, it helps to go prepared. You might ask:

• Which medicine do you think is suitable for me, and why?
• What dose will I start on, and how will it be increased?
• What side effects should I expect, and what should I do if they happen?
• Which of my current medicines might be affected, and do any doses need changing?
• What should I do about contraception, if relevant?
• How often will I be reviewed, and by whom?
• How will we judge whether the treatment is working?
• What is the plan if I want to stop, or if I need to pause for surgery or pregnancy?
• Will you share information with my GP?

A good prescriber will welcome these questions. Bring a list of all your medicines, including over-the-counter products and supplements, and any recent blood test results. Be honest about your medical history, including any history of eating disorders, pancreatitis, gallbladder problems or thyroid conditions. This information is there to keep you safe, and the decision about whether to prescribe rests with the prescriber.

Choosing a provider

If you are considering private treatment, look for a provider registered with the appropriate regulators, a thorough consultation that covers your medical history and other medicines, identity and weight checks, clear follow-up and support, and willingness to share information with your GP. Our guides to how to choose an online pharmacy for weight loss and who regulates online weight loss services explain the checks, and our provider comparison and service comparisons show how regulated services differ.

For related reading, browse our frequently asked questions guides, or visit our hubs for weight loss injections and oral GLP-1 tablets.

When to speak to a professional

Speak to your GP, a pharmacist or your prescriber:

• before starting a GLP-1 medicine, with a full list of your other medicines
• if you are pregnant, planning a pregnancy, breastfeeding or using oral contraception
• if you have surgery, sedation or an endoscopy planned
• if side effects are troublesome or not settling
• if you notice changes in mood, or have a history of an eating disorder or depression

Seek urgent medical help (call NHS 111, or 999 in an emergency) if you are taking a GLP-1 medicine and have:

• severe, persistent abdominal pain, which may spread to your back, with or without vomiting (a possible sign of pancreatitis)
• pain in the upper right abdomen with fever or yellowing of the skin or eyes (possible gallbladder problems)
• signs of severe dehydration, such as very little urine, confusion or fainting
• thoughts of harming yourself; you can also contact Samaritans on 116 123
• signs of a severe allergic reaction, such as swelling of the face, lips or throat, or difficulty breathing

Suspected side effects can be reported to the MHRA through the Yellow Card scheme.