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
Wegovy as a Weight Loss Drug in the UK
Wegovy is a prescription-only weekly weight loss injection licensed in the UK that contains semaglutide, a GLP-1 receptor agonist. It's designed to help adults with obesity or overweight manage their weight alongside diet and exercise. Understanding how to access Wegovy through the NHS and the evidence behind its effectiveness can help you explore whether this weekly weight loss injection might be suitable for your situation. Our GLP-1 weight loss calculator can help you estimate potential results at different doses.
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.
NHS Eligibility and Access to Wegovy in the UK
Wegovy is available in the UK through two routes: NHS specialist services and private prescribing. NHS eligibility requires a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with at least one weight-related health condition such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — eligibility may start at BMI 27.5 or above.
NHS access is through tier 3 specialist weight management services following referral from your GP. However, availability varies significantly by region, and waiting times can be substantial. The STEP-1 clinical trial showed that semaglutide helped participants lose an average of approximately 15% of their body weight over 68 weeks, though individual results vary considerably.
- Starting dose: 0.25 mg weekly
- Maximum dose: 2.4 mg weekly
- Dose escalation: typically every 4 weeks
- Treatment duration: ongoing, with periodic reviews
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 Routes for Wegovy in the UK
The NHS route offers access without upfront cost but involves referral to specialist services, clinical assessment, and often lengthy waiting lists. Your GP can refer you to your local tier 3 weight management service, which will assess your suitability and manage your treatment.
The private route allows direct access through UK-licensed online prescribers without NHS referral, with assessment and prescription typically available within days. Private costs range from approximately £130–£300 monthly depending on dose. Both routes require a clinical assessment confirming prescription eligibility. Use our BMI calculator to check your current BMI, and track your progress using 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.
Is Wegovy available on the NHS in the UK?
Wegovy is available through NHS tier 3 specialist weight management services for adults meeting eligibility criteria (BMI ≥30 or ≥27 with weight-related health conditions). Access is through GP referral, though regional availability and waiting times vary significantly. Your GP can advise on local NHS provision.
How much weight can you lose with Wegovy?
In clinical trials, Wegovy helped participants lose an average of approximately 15% of body weight — though individual results vary considerably. This equals roughly 15 kg for someone weighing 100 kg. Weight loss depends on dose, adherence, diet, and exercise. Results are not assured.
What is the difference between Wegovy and Mounjaro for weight loss?
Wegovy (semaglutide) is a GLP-1 receptor agonist; Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist. Clinical trials suggest Mounjaro may produce slightly greater average weight loss (approximately 20% vs 15%), but individual responses vary. Both require prescription and clinical assessment.
How much does Wegovy cost privately in the UK?
Private Wegovy costs typically range from £130–£300 per month depending on dose and provider. This is for the medication only; prescribing fees may apply separately. NHS access is free but involves referral and waiting times. Compare costs with your chosen prescriber.
What are the main side effects of Wegovy?
Common side effects include nausea, diarrhoea, vomiting, constipation, and stomach pain — particularly during dose escalation. Most side effects diminish over time. Serious but rare side effects include pancreatitis and gallbladder problems. Report any concerning symptoms to your prescriber immediately.
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.