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
Weight Loss Clinics in the UK — Your Complete Guide
If you're searching for weight loss clinic support, you may not realise that weight management in the UK is delivered through a structured NHS pathway or private clinics, not traditional "clinics" as found elsewhere. The NHS offers free support through tier 1–4 weight management services, whilst private options include prescription weight loss medication through online assessment. Our free BMI calculator and GLP-1 weight loss calculator can help you understand your starting point and explore what treatment may suit you.
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.
How UK Weight Loss Services Work
Weight management in the UK follows a tiered NHS approach. Tier 1 includes self-help resources, community programmes, and digital tools — like the weight converters and BMI tracking tools available here on MyWeightCheck. Tier 2 involves primary care-based interventions through your GP, often including structured behaviour change programmes such as the NHS Weight Loss Plan. Tier 3 offers specialist multidisciplinary weight management services where prescription weight loss medication may be introduced. Tier 4 is reserved for bariatric (weight loss) surgery in cases of severe obesity with significant health complications. Access varies significantly by region — your local Integrated Care Board (ICB) determines availability and waiting times. If you're looking for prescription weight management medication like Wegovy (semaglutide), you'll typically need referral to a tier 3 service, though private online prescribing is also available following clinical assessment.
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.
Prescription Weight Loss Options Available
Several prescription-only weight loss medications are licensed in the UK. Wegovy (semaglutide) is a once-weekly GLP-1 injection that, in clinical trials, helped participants lose an average of approximately 15% of body weight — though individual results vary significantly. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that achieved average weight loss of 15–21% in trials. Saxenda (liraglutide) is a daily GLP-1 injection. All are prescription-only and require assessment by a qualified prescriber. Use our free GLP-1 weight loss calculator above to explore potential outcomes at different doses and understand how these medications may support your weight management journey alongside diet and increased physical activity.
- 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 do I access weight loss support on the NHS?
Contact your GP to discuss your weight and health goals. They may refer you to a tier 1 self-help programme first, or directly to tier 2 or 3 services depending on your BMI and health conditions. NHS services are free but waiting lists vary by region — ask your ICB about local availability and timescales.
What is the difference between Wegovy and Ozempic?
Both contain semaglutide, but Wegovy is specifically licensed for weight management at doses up to 2.4 mg weekly. Ozempic is licensed for type 2 diabetes (up to 2 mg) and is not approved for weight loss in the UK. Using Ozempic for weight loss is off-label and not recommended.
Can I get prescription weight loss medication privately without NHS referral?
Yes. Private online prescribing services allow you to have a consultation with a UK-licensed prescriber and receive a prescription for medications like Wegovy or Mounjaro if clinically appropriate. A GPhC-registered pharmacy dispenses the medication. Costs vary but typically range from £129–£320 monthly depending on dose.
How much weight can I expect to lose with GLP-1 medication?
Clinical trials show average weight loss of 15–21% of body weight over several months — but individual results vary significantly. Results depend on the dose, your starting weight, adherence, diet, and exercise. Always use our GLP-1 weight loss calculator to estimate potential outcomes based on your situation.
What eligibility criteria apply for prescription weight loss treatment?
Generally, adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, heart disease, sleep apnoea), may be eligible. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. A prescriber assesses individual eligibility.
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.