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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Semaglutide Weight Loss Reviews: What the NHS Evidence Shows
Semaglutide is a prescription-only weekly injection licensed in the UK for weight management, available as Wegovy. Real-world reviews and clinical trial data show significant weight loss results for eligible adults. This guide explains what the evidence shows, NHS eligibility criteria, and how to access semaglutide through both NHS specialist services and private prescribing in the UK. Individual results vary considerably based on dose, lifestyle changes, and personal factors.
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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.
NHS Eligibility and STEP Trial Evidence for Semaglutide
Semaglutide (Wegovy) is a GLP-1 receptor agonist that works by reducing appetite and helping you feel fuller after smaller meals. In the landmark STEP-1 clinical trial, participants receiving semaglutide at the maximum dose of 2.4 mg lost an average of approximately 14.9% of their body weight over 68 weeks, alongside a reduced-calorie diet and increased physical activity.
NHS eligibility for semaglutide requires:
- BMI of 30 kg/m² or above, OR
- BMI of 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, dyslipidaemia, sleep apnoea, or cardiovascular disease)
- Lower thresholds apply for South Asian, Chinese, Black African, or Black Caribbean adults
Access is through tier 3 specialist weight management services following a GP referral. Availability and waiting times vary significantly by region.
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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: How to Access Semaglutide in the UK
NHS route: Referral from your GP to a specialist weight management service. Free on the NHS once prescribed, but waiting lists can be lengthy (sometimes 6–18 months depending on your area). Prescribers will monitor your progress regularly.
Private route: Online consultation with a UK-licensed prescriber, available without NHS referral. Private prescription costs range from approximately £100–£300 per month depending on dose. Eligibility is assessed individually during an online clinical assessment. Both routes require a prescription — semaglutide is not available over the counter.
Whichever route you choose, use our GLP-1 weight loss calculator to estimate potential outcomes at different doses, and our BMI calculator to assess your starting point.
- 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.
Does semaglutide really work for weight loss in the UK?
Yes. The STEP-1 clinical trial (the gold standard evidence) showed average weight loss of 14.9% of body weight on 2.4 mg semaglutide over 68 weeks, alongside lifestyle changes. Real-world UK reviews from patients on NHS and private prescriptions generally report similar results, though individual outcomes vary. Some lose more, some less — it depends on adherence, diet, exercise, and personal metabolism.
What is the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy (2.4 mg) is licensed specifically for weight management in the UK. Ozempic is approved for type 2 diabetes (doses up to 2 mg) and is not licensed for weight loss. Using Ozempic for weight loss would be off-label. Always ensure your prescription specifies Wegovy if you're seeking weight management treatment.
How long does semaglutide take to show weight loss results?
Most people notice appetite reduction within 1–2 weeks. Meaningful weight loss typically becomes apparent after 4–8 weeks of consistent use at an effective dose. The STEP trials measured results over 68 weeks. Weight loss is not linear — expect plateaus. Combining semaglutide with a reduced-calorie diet and regular physical activity produces the best results.
Are semaglutide reviews positive from NHS patients?
Generally yes, but experiences vary. NHS reviews often mention difficulty accessing treatment due to waiting lists, and some report side effects (nausea, diarrhoea) that diminish over time. Those who complete treatment report significant weight loss and improved health markers. Negative reviews sometimes reflect unmet expectations or side effect challenges rather than ineffectiveness.
Can I get semaglutide on the NHS if I have a BMI of 28?
If your BMI is 27–29.9, you're eligible only if you have at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, dyslipidaemia, sleep apnoea, or cardiovascular disease). Speak to your GP about referral to a specialist weight management service. If you don't have an eligible condition, private prescribing may be an option — check current eligibility criteria with a private provider.
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.