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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Ozempic Weight Loss Dose — What You Need to Know
Ozempic is often searched for weight loss, but it's important to clarify that Ozempic isn't licensed for weight management in the UK — it's approved for type 2 diabetes only. Wegovy, which contains the same active ingredient (semaglutide), is the UK-licensed version specifically for weight management. If you're interested in prescription weight loss medication, understanding the correct licensed option and how dosing works is essential. This guide explains the difference and what eligibility looks like under NHS weight loss and prescription weight loss UK frameworks.
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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.
Ozempic vs Wegovy — The Key Difference
Both Ozempic and Wegovy contain semaglutide, but they are licensed for different uses in the UK:
- Ozempic: Licensed for type 2 diabetes management only, with doses up to 2 mg once weekly. Using Ozempic for weight loss is considered off-label and is not recommended.
- Wegovy: The licensed weight management version, available at doses up to 2.4 mg once weekly. Wegovy is the prescription-only medication specifically approved for weight management in UK adults.
Both contain identical active ingredient (semaglutide), a GLP-1 receptor agonist that may help reduce appetite and support feeling fuller after meals. However, only Wegovy should be used for weight loss because it's been specifically assessed and approved for this purpose by UK regulators. If you're looking for glp-1 weight loss options in the UK, Wegovy is the licensed choice, alongside Mounjaro (tirzepatide), which offers a dual GIP and GLP-1 mechanism.
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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.
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Wegovy Dosing and What to Expect
Wegovy follows a stepped dosing schedule, increasing gradually over 16 weeks to reach the maximum maintenance dose of 2.4 mg weekly. Starting dose is 0.25 mg, increasing by 0.25 mg every 4 weeks through 0.5 mg, 1 mg, and 1.7 mg, before reaching 2.4 mg. Clinical trials (STEP-1) showed participants lost an average of approximately 15% of body weight on 2.4 mg, though individual results vary significantly. Weight loss medication works best alongside a reduced-calorie diet and increased physical activity. Use our free GLP-1 weight loss calculator to estimate potential weight loss outcomes at different doses. To check whether you might be eligible for prescription weight loss medication, try our free BMI calculator and understand your starting point under NHS weight loss eligibility criteria.
- 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.
Why is Ozempic not used for weight loss in the UK?
Ozempic is licensed only for type 2 diabetes management in the UK, not for weight loss. Wegovy is the semaglutide version specifically approved and assessed for weight management. Using Ozempic off-label for weight loss is not recommended because it hasn't undergone the same regulatory approval process for this indication. Always use licensed medications as intended.
What is the maximum dose of Wegovy for weight management?
The maximum dose of Wegovy is 2.4 mg once weekly. The dose is increased gradually over 16 weeks, starting at 0.25 mg and increasing every 4 weeks. Your prescriber will determine the appropriate dose for you based on your individual health and response.
How much weight can you lose with Wegovy?
Clinical trials showed an average weight loss of approximately 15% of body weight at 2.4 mg over 68 weeks, alongside dietary changes and exercise. However, individual results vary significantly — some people lose more, others less. Weight loss depends on diet adherence, physical activity, genetics, and other health factors.
Is Wegovy available on the NHS for weight management UK?
Wegovy may be available through NHS specialist tier 3 weight management services, but access varies by region and availability is limited. Many people access Wegovy privately through online prescribing following a clinical assessment. Your GP can discuss the best option for you.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with doses up to 15 mg weekly, while Wegovy (semaglutide) is a GLP-1 agonist only with a maximum dose of 2.4 mg. Both are prescription-only and licensed for weight management. Mounjaro showed slightly higher average weight loss in trials, but both require clinical assessment and lifestyle changes for best results.
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.