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
Semaglutide For Weight Loss — How to Access It in the UK
Semaglutide is a prescription-only weekly weight loss injection licensed in the UK for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Available under the brand name Wegovy, this GLP-1 receptor agonist may help reduce appetite and support weight management alongside diet and activity changes. Access in the UK is through two main routes: NHS specialist services or private online prescribing. Understanding your options, costs, and what to expect can help you make an informed decision about whether this treatment is right for you.
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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 Cost and Access Routes for Semaglutide
NHS access: Semaglutide (Wegovy) is available through NHS specialist tier 3 weight management services, but not through standard GP prescriptions. You'll need referral from your GP to a specialist service in your area. NHS availability varies significantly by region — some areas have long waiting lists of several months or longer. Once approved, the NHS covers the full cost of the medication.
Private online access: You can obtain semaglutide through GPhC-registered UK pharmacies following an online clinical assessment. Private costs typically range from £129–£250 per month depending on dose, with starting doses costing less than maintenance doses. Semaglutide 2.4 mg (the maximum dose) is usually the most expensive option. Payment is per prescription, and you can start treatment within days of assessment rather than waiting months on an NHS list. Some private providers offer subscription models or bulk purchase discounts.
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 — Which Route Is Right for You?
The NHS route is free but involves a GP referral, specialist assessment, and potentially significant waiting times. It's suitable if you have the time to wait and prefer NHS care at no cost. The private route is faster — typically days from consultation to first injection — but involves direct costs. A private online consultation with a UK-licensed prescriber takes 10–20 minutes and covers your health history, medications, and suitability. Once approved, your prescription is dispensed by a GPhC-registered pharmacy. Use our free GLP-1 weight loss calculator to explore projected weight loss at different doses, and track your progress with our free progress tracker once you start treatment.
- 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.
How much does semaglutide cost on the NHS in the UK?
Semaglutide (Wegovy) is free on the NHS when prescribed through specialist tier 3 weight management services. However, you must be referred by your GP and wait for a specialist assessment. Availability varies by region — some areas have limited capacity and long waiting lists.
What's the typical cost of semaglutide through private prescribing in the UK?
Private costs range from approximately £129–£250 per month depending on your dose. Lower starting doses (0.25–0.5 mg) cost less, while the maximum dose of 2.4 mg costs more. Online consultations typically cost £20–£50, and some providers offer monthly or quarterly subscription discounts.
How quickly can I start semaglutide privately?
Private online assessments can be completed within 1–2 days, and if approved, your first prescription can be dispensed within 3–5 working days. This is significantly faster than NHS routes, where waiting times often span months.
Do I need a GP referral for private semaglutide prescribing?
No. Private online prescribing does not require a GP referral. A UK-licensed prescriber will assess your suitability through an online consultation. However, it's recommended you inform your GP that you're taking semaglutide, as it may interact with other medications.
Is semaglutide for weight loss the same as Ozempic?
Both contain semaglutide, but they're different products. Wegovy (semaglutide 2.4 mg) is licensed for weight management, while Ozempic (semaglutide up to 2 mg) is licensed for type 2 diabetes. Using Ozempic for weight loss is off-label in the UK. Always ensure you're prescribed the correct product for your intended use.
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.