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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GLP-1 Weight Loss and the NHS in the UK
GLP-1 medications are prescription-only weight management injections now available through NHS specialist services in the UK. If you're wondering how to access GLP-1 treatment like Wegovy or Mounjaro, or whether you're eligible, it's important to understand how the NHS health system works with these medications. This guide explains NHS access, eligibility criteria, and what the current health advice recommends for weight management in the UK.
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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.
How GLP-1 Works and NHS Approval
GLP-1 stands for glucagon-like peptide-1, a natural hormone your gut produces after eating. GLP-1 receptor agonist medications mimic this hormone to help regulate appetite, support feeling fuller after smaller meals, and slow how quickly food leaves your stomach. In the UK, Wegovy (semaglutide) and Mounjaro (tirzepatide) are both licensed for weight management and prescribed through NHS specialist services.
The NHS has approved these medications for adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. NICE (National Institute for Health and Care Excellence) guidance now supports GLP-1 use within specialist tier 3 and tier 4 weight management services across England, Scotland, Wales, and Northern Ireland.
- Wegovy: once-weekly injection, GLP-1 agonist only
- Mounjaro: once-weekly injection, dual GIP and GLP-1 agonist
- Saxenda: daily injection, GLP-1 agonist (also available)
Clinical trials showed average weight loss of 14–21% of body weight, though individual results vary significantly.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Accessing GLP-1 Through the NHS
To access GLP-1 medication on the NHS, you'll typically need a referral from your GP to a specialist tier 3 weight management service in your area. Availability varies significantly by region—some NHS areas have extensive programmes, while others have limited services or long waiting lists.
Your GP will assess whether specialist referral is appropriate based on your health. At the specialist service, a multidisciplinary team (doctors, nurses, dietitians) will review your eligibility, discuss risks and benefits, and monitor you throughout treatment.
Private options are also available through GPhC-registered online pharmacies following a clinical assessment—these offer faster access than NHS waiting lists but at personal cost. Use our free BMI calculator above to check your current BMI and assess potential eligibility criteria. Check your local NHS integrated care board website to find weight management services in your area.
NHS health guidance emphasises that GLP-1 medications work best alongside a reduced-calorie diet and increased physical activity—they're not a replacement for lifestyle changes. Your GP or specialist can give personalised NHS health advice about whether this treatment is right for you.
Costs on the NHS are covered by the health system if prescribed through a specialist service. Privately, GLP-1 injections typically cost £129–£320 per month depending on dose. Before starting any weight loss medication, your prescriber will assess your individual health, review contraindications, and monitor you regularly.
- 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.
Can I get GLP-1 medication like Wegovy on the NHS?
Yes, Wegovy (semaglutide) and Mounjaro (tirzepatide) are available through NHS specialist weight management services. Access requires a referral from your GP and assessment by a tier 3 specialist service. Availability and waiting times vary significantly by region. Your GP can advise on local services and whether you meet eligibility criteria.
What's the difference between Ozempic and Wegovy?
Both contain semaglutide, but Ozempic is licensed for type 2 diabetes (up to 2 mg dose) and is NOT approved for weight loss in the UK. Wegovy is the licensed weight management version (up to 2.4 mg). Using Ozempic for weight loss would be off-label and not recommended through the NHS for weight management.
Am I eligible for GLP-1 on the NHS?
NHS eligibility includes adults with BMI 30 or above, or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply. Your GP will assess your individual eligibility.
How much does GLP-1 cost on the NHS?
GLP-1 prescribed through NHS specialist services is free at the point of use (covered by the NHS). Private options cost £129–£320 per month depending on dose and provider. Costs for private treatment are not covered by NHS prescription charges.
What weight loss should I expect with GLP-1?
Clinical trials showed average weight loss of 14–21% of body weight over 68–72 weeks when combined with diet and exercise. Individual results vary significantly—some people lose more, some less. Your prescriber can discuss realistic expectations based on your health and circumstances. Try our 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.