The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Weight Loss Hunger Suppressant Medications in the UK
A hunger suppressant medication can help you feel fuller for longer and reduce food cravings as part of a structured weight management programme. In the UK, several prescription-only medications are licensed for weight loss and work by suppressing appetite. These are not a substitute for healthy eating and exercise, but evidence suggests they can support sustainable weight loss when used alongside lifestyle changes. This guide explains the prescription options available through the NHS and private healthcare, who might be eligible, and how to start a conversation with your GP about whether hunger suppressant medication could be right for you.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
UK-Licensed Weight Loss Medications — What's Available?
Three prescription-only appetite suppressant medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist injection given once weekly. Clinical trials showed average weight loss of around 15–21% of body weight over 72 weeks, though individual results vary significantly.
- Wegovy (semaglutide) — a GLP-1 receptor agonist injection given once weekly. Clinical trial data demonstrated average weight loss of approximately 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — a GLP-1 receptor agonist given as a daily injection. Average weight loss is typically around 5–10% of body weight.
All three work by signalling to your brain that you are fuller and more satisfied after eating smaller portions, while also slowing how quickly food moves through your stomach. Your prescriber will assess which option suits your individual health profile and lifestyle.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS vs Private Access — How to Get Started
Via the NHS: Prescription weight loss medication is available through specialist tier 3 weight management services. Your GP can refer you if you meet eligibility criteria (typically BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or sleep apnoea). NHS services are free but waiting lists can be lengthy in some areas.
Via private prescribing: If you prefer not to wait, several UK-registered online prescribing services offer weight loss medications following a clinical assessment. This route is faster but involves payment. Either way, you'll need a clinical consultation to confirm the medication is safe for your individual health profile.
Start by discussing weight management options with your GP — they can advise on NHS eligibility and local services available to you.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Do weight loss hunger suppressant medications work without dieting?
No. Prescription appetite suppressant medications are designed to work alongside a reduced-calorie diet and increased physical activity. They are not a substitute for lifestyle changes. Clinical trials showed weight loss was achieved when medication was combined with a healthy diet and exercise programme. Medication helps reduce cravings and portion sizes, making it easier to stick to these changes.
What does it feel like when hunger suppressant medication starts working?
Most people report feeling fuller after smaller meals, reduced cravings for certain foods, and less frequent desire to snack between meals. Some people experience mild nausea or changes in appetite during the first few weeks as their body adjusts. These effects usually settle down. Individual experiences vary — some people feel suppressed appetite within days; others take several weeks on the same dose to notice changes.
How long do I need to take weight loss hunger suppressant medication?
This depends on your individual goals and how your body responds. Some people take it for several months to lose a target amount of weight, then stop. Others continue longer term to help maintain weight loss. Your prescriber will discuss how long treatment is appropriate for you. You should not stop suddenly — your prescriber will advise on how to stop safely if needed.
Am I eligible for weight loss hunger suppressant medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or a BMI of 27–29.9 with a weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply. Ask your GP to refer you to a specialist weight management service to assess your eligibility. Use our free BMI calculator above to check your current BMI.
What's the difference between Mounjaro and Wegovy for weight loss?
The main differences are their mechanism (Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1 only) and injection frequency (both are weekly). Mounjaro achieved slightly higher average weight loss in clinical trials, but results vary between individuals. Both require a prescription and clinical assessment. Your prescriber will recommend the most suitable option based on your health profile, other medications, and individual circumstances. Try our free GLP-1 weight loss calculator to estimate potential outcomes.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.