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
When Will Wegovy Be Available on the NHS?
Wegovy (semaglutide) remains extremely limited on the NHS despite being licensed for weight management in the UK. Currently, access is primarily through specialist tier 3 weight management services in specific regions—not standard GP prescription. Many NHS areas have no access at all due to funding constraints. For most UK adults seeking this GLP-1 receptor agonist treatment, private prescription through a licensed prescriber following an online clinical assessment remains the most accessible route. Understanding your options—including comparing Wegovy with Mounjaro, the alternative dual GIP+GLP-1 receptor agonist also available—can help you make an informed decision about weight management treatment.
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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.
Wegovy vs Mounjaro: Trial Data and How They Work Differently
Mechanism differences: Wegovy is a GLP-1 receptor agonist only, activating one hormone pathway. Mounjaro is a dual GIP and GLP-1 receptor agonist, meaning it activates two pathways simultaneously—which may explain why some clinical trial data suggests slightly higher average weight loss with Mounjaro.
Clinical trial results: In the STEP-1 trial, Wegovy achieved approximately 14.9% average body weight loss at the maximum dose of 2.4 mg over 68 weeks. Mounjaro's SURMOUNT-1 trial showed approximately 15–21% average body weight loss depending on dose (5 mg to 15 mg) over 72 weeks. Both studies included participants following a reduced-calorie diet and increased physical activity—individual results vary significantly.
Dosing schedule: Both are once-weekly injections, but starting doses differ: Wegovy begins at 0.25 mg; Mounjaro begins at 2.5 mg. Escalation timelines also differ, affecting how quickly you reach therapeutic 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.
Eligibility and How to Access Treatment in the UK
NHS access: Wegovy eligibility through NHS tier 3 services typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. However, availability varies drastically by region and waiting lists can be extremely long. Your GP can enquire whether your local Integrated Care Board (ICB) offers access, though many do not.
Private access: Both Wegovy and Mounjaro are available through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber. A prescriber will assess your medical history, current medications, and suitability—this clinical assessment ensures safe prescribing regardless of access route. Try our GLP-1 weight loss calculator to explore potential outcomes with either medication, and use our BMI calculator to check your current category.
- 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 Wegovy on the NHS in 2024/2025?
Wegovy is licensed for NHS use, but real-world access is extremely limited. Only specialist tier 3 weight management services in certain regions prescribe it, and many areas have no NHS provision at all. Waiting lists where available can be months to years. Private prescription remains the most practical access route for most UK adults seeking this treatment.
How does Wegovy compare to Mounjaro for weight loss?
Clinical trials show both are effective. Wegovy (STEP trial) averaged clinically studied weight loss; Mounjaro (SURMOUNT trial) averaged 15–21% depending on dose. Mounjaro's dual mechanism (GIP+GLP-1) differs from Wegovy's single GLP-1 mechanism, though individual results vary greatly and depend on adherence, diet, and activity level.
What's the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is licensed specifically for weight management and available at the higher 2.4 mg dose. Ozempic is approved for type 2 diabetes (up to 2 mg) and is not licensed for weight loss in the UK. Using Ozempic off-label for weight loss is not recommended—Wegovy is the appropriate UK-licensed option.
Which is better for me—Wegovy or Mounjaro?
Neither is universally "better"—suitability depends on your individual health, medical history, medications, and how your body responds. A licensed prescriber will assess you and recommend the most appropriate option. Both require a prescription following clinical assessment; both are prescription-only medicines.
How do I access Wegovy in the UK right now?
Contact your GP to ask about NHS tier 3 specialist weight management services in your area—access is being gradually rolled out but varies significantly by region. For immediate access, a GPhC-registered online pharmacy can facilitate a private prescription following a consultation with a licensed UK prescriber who will conduct a full clinical assessment.
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.