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
Free tracker included with every download this week
Is Ozempic Used for Weight Loss in the UK?
Ozempic is often mentioned in relation to weight loss, but there's important clarification needed: Ozempic is a diabetes medication and is NOT licensed for weight loss in the UK. However, semaglutide — the same active ingredient — is available as Wegovy, which IS licensed specifically for weight management. This guide explains the difference, how weight management works in the UK, and what prescription options are actually available for adults seeking professional support with weight loss.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Ozempic vs Wegovy — Understanding the Difference
Both Ozempic and Wegovy contain semaglutide, but they are different medicines with different licensed uses in the UK:
- Ozempic is approved for type 2 diabetes management at doses up to 2 mg. Using it for weight loss is off-label and not recommended — it is not licensed for this purpose.
- Wegovy is the licensed weight management version, approved specifically for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Maximum dose is 2.4 mg once weekly.
- In clinical trials (STEP-1), Wegovy helped participants lose an average of approximately 15% of body weight over 68 weeks, alongside reduced-calorie diet and increased physical activity. Individual results vary significantly.
- Both are GLP-1 receptor agonists — they work by activating natural hormones that help regulate appetite and blood sugar.
If you're searching for "weight loss Ozempic UK", you likely need Wegovy, not Ozempic. Only a licensed prescriber can assess which medication is suitable for you.
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.
How to Access Weight Loss Support in the UK
There are several pathways to weight management support in the UK. The NHS offers referral to specialist tier 3 weight management services through your GP — these assess eligibility and may offer prescription medications like Wegovy alongside behaviour change support. However, NHS waiting lists can be lengthy in many areas, and regional availability varies.
Privately, adults can access Wegovy and other GLP-1 medications through licensed online prescribers following a clinical assessment. Try our GLP-1 weight loss calculator to understand potential outcomes at different doses. Weight management is most effective when combined with sustainable dietary changes and increased physical activity — not medication alone. Your GP can discuss which approach is right for your circumstances.
- 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 buy Ozempic for weight loss in the UK?
No. Ozempic is not licensed for weight loss in the UK and should only be prescribed for type 2 diabetes. Using it off-label for weight management is not recommended. Wegovy is the licensed semaglutide option for weight management in the UK.
What's the difference between Ozempic and Wegovy?
Both contain semaglutide but serve different purposes. Ozempic (diabetes) goes up to 2 mg. Wegovy (weight management) goes up to 2.4 mg and is specifically licensed for weight loss. Only Wegovy should be used for weight management in the UK.
How much weight can I expect to lose with Wegovy?
In the STEP-1 clinical trial, participants lost an average of approximately 15% of body weight over 68 weeks on 2.4 mg, alongside diet and exercise changes. Results vary significantly between individuals. Your GP or prescriber can discuss realistic expectations.
How do I access Wegovy in the UK?
Through NHS specialist weight management services (referral from your GP) or privately via licensed online prescribers. Both require a clinical assessment. The GLP-1 weight loss calculator can help you explore potential outcomes. NHS access varies by region and may involve waiting lists.
Is weight loss medication safe?
GLP-1 medications like Wegovy are prescribed by licensed healthcare professionals following clinical assessment. Side effects are common (nausea, diarrhoea) but usually manageable. Serious side effects are rare. Your prescriber discusses risks and benefits before starting treatment.
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.