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 Ozempic UK — Understanding Your Options
Ozempic (semaglutide) is a diabetes medication, not licensed for weight loss in the UK — though this is a common question. If you're interested in prescription weight management, the UK has several licensed alternatives specifically approved for weight loss. This guide explains what's available, who is eligible, and how to access treatment through both NHS and private routes.
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Calculate Your BMI Instantly
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
The UK has three prescription medications specifically licensed for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide 2.4mg), and Saxenda (liraglutide). While Ozempic contains semaglutide, it is approved only for type 2 diabetes at lower doses — using it for weight loss is off-label and not recommended. Wegovy is the licensed weight loss version of semaglutide at 2.4mg.
- Mounjaro: Dual GLP-1 and GIP receptor agonist, once-weekly injection, doses 2.5mg to 15mg. Clinical trials showed average weight loss of 15–21% body weight.
- Wegovy: GLP-1 receptor agonist, once-weekly injection, doses 0.25mg to 2.4mg. Clinical trials showed average weight loss around 15% body weight.
- Saxenda: GLP-1 receptor agonist, daily injection, doses 0.6mg to 3mg. Established option with long safety data.
All three are prescription-only and require clinical assessment before being prescribed. Use our free GLP-1 weight loss calculator above to explore potential outcomes at different doses.
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.
NHS vs Private Access — How to Get Started
NHS access: NICE has approved tirzepatide (Mounjaro) for specialist tier 3 weight management services. Ask your GP for a referral to your local NHS weight management service, though waiting lists vary significantly by region and can be lengthy. Private access: Prescription weight loss medications are available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber — no NHS referral required.
Eligibility typically includes adults with a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Use our free BMI calculator to check your personal BMI, then discuss options with your GP or a private prescriber to find out if treatment is appropriate for 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.
Is Ozempic licensed for weight loss in the UK?
No. Ozempic (semaglutide) is approved in the UK only for type 2 diabetes management at doses up to 2mg. Using it for weight loss is off-label and not recommended. Wegovy is the licensed weight loss version of semaglutide (2.4mg dose) specifically approved for weight management in the UK.
Who is eligible for prescription weight loss medication in the UK?
Generally, adults with a BMI of 30 or above, or 27 or above with weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease, sleep apnoea, or dyslipidaemia). Lower BMI thresholds may apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. A healthcare professional will assess your individual eligibility.
How much weight can I lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% for Mounjaro and around 15% for Wegovy, though individual results vary significantly. These results were achieved alongside a reduced-calorie diet and increased physical activity. Your actual weight loss depends on many factors including dose, adherence, diet, and exercise.
Can I get prescription weight loss medication on the NHS?
Yes, NICE has approved Mounjaro for NHS specialist tier 3 weight management services. Availability varies by region and waiting lists can be long. Ask your GP for a referral to your local NHS weight management service to find out about access in your area.
How do I know which weight loss medication is right for me?
A GP or licensed prescriber will assess your medical history, current medications, BMI, and health conditions to recommend the most suitable option. Mounjaro (dual GIP/GLP-1) and Wegovy (GLP-1 only) are the most commonly prescribed in the UK. Use our weight loss calculator to explore potential outcomes, then discuss with a healthcare professional.
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.