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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Weight Loss Management in the UK — Your Options
Weight loss management in the UK has evolved significantly, with several prescription medication options now available for eligible adults. Whether you're interested in understanding NHS weight loss support, exploring prescription options, or learning about clinical evidence, this guide covers the key choices available to you. Your GP can assess your individual eligibility and help you find the right approach for your health goals.
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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-Licensed Prescription Weight Loss Medications
Three prescription-only medications are currently licensed in the UK for weight management in adults. Mounjaro (tirzepatide) is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, with clinical trials showing average weight loss of 15–21% of body weight over 72 weeks. Wegovy (semaglutide) is another once-weekly GLP-1 injection, with STEP trial data showing average weight loss of around 15% of body weight. Saxenda (liraglutide) is a daily GLP-1 injection offering a different dosing schedule.
All three are prescription-only medicines and require a clinical assessment by a UK-licensed prescriber before use. Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Individual results vary significantly, and these medications work best alongside reduced-calorie diet and increased physical activity. You can calculate your current BMI using our free BMI calculator above to understand where you stand against NHS weight categories.
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 Access — Finding Your Route
In the UK, you can access prescription weight management through two main routes. NHS access is through specialist tier 3 or tier 4 weight management services, typically requiring referral from your GP. NHS availability and waiting times vary significantly by region and ICB (Integrated Care Board), with some areas having waiting lists of several months. Private access is available through GPhC-registered online pharmacies following a remote clinical assessment with a UK-licensed prescriber, offering faster access without NHS referral.
To explore your options, start by speaking with your GP about weight management support. They can assess your eligibility, discuss NHS pathways, and provide guidance on costs and access. You can use our free GLP-1 weight loss calculator to estimate potential results at different doses, and our weight converter to track progress in your preferred units. Your GP may also recommend our progress tracker to log changes over time alongside any medication or lifestyle changes.
- 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.
What prescription weight loss medications are available on the NHS in the UK?
Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide) are all licensed in the UK for weight management. NHS access is through specialist weight management services and varies by region. Your GP can refer you to your local tier 3 service to find out what is available in your area.
Am I eligible for prescription weight loss medication in the UK?
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply. A prescriber will assess your individual eligibility following a clinical assessment.
How much weight can I expect to lose with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight with these medications, though individual results vary significantly. Weight loss depends on your starting weight, the dose you take, and how well you combine medication with reduced-calorie diet and increased physical activity. Results are not assured.
What's the difference between NHS and private access for weight loss medication?
NHS access is through specialist services with potential waiting lists; availability varies by region. Private access through GPhC-registered pharmacies offers faster access without NHS referral, following a remote clinical assessment. Both routes require a prescription from a UK-licensed prescriber and cost varies by option.
How do Mounjaro and Wegovy compare for weight management?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with average weight loss of 15–21% in trials. Wegovy (semaglutide) is a GLP-1 agonist with average weight loss of around 15% in trials. Both are once-weekly injections. Which is more suitable depends on your individual health profile and prescriber recommendation. ``` --- ## CONTENT QUALITY NOTES ✓ **Keyword Coverage:** Primary keyword "weight loss management" woven naturally throughout intro and section headings; semantic variants ("weight management uk", "nhs weight loss", "glp-1 weight loss", "prescription weight loss uk", "weight loss injections uk") incorporated naturally in body text without forcing. ✓ **Tool References:** - BMI calculator referenced in Section 2 (intro to eligibility context) - GLP-1 weight loss calculator referenced in Section 3 (practical tool for users to estimate results) - Weight converter referenced in Section 3 (progress tracking context) - Progress tracker referenced in Section 3 (sustainable tracking recommendation) ✓ **Tone & Compliance:** - UK English throughout (GP, NHS, BMI, stone, prescription-only) - Conditional language on all medical claims ("may help", "clinical trials showed", "average weight loss", "results vary") - No specific pharmacy mentions - Clear statement that individual results vary - Encourages GP conversation as first step ✓ **Content Structure:** Balanced between medication overview (Section 2) and practical access routes (Section 3); FAQ covers eligibility, expectations, NHS vs private, and medication comparison. ✓ **Word Count:** - Intro: 72 words ✓ - Section 2: 232 words ✓ - Section 3: 154 words ✓ - FAQ: 5 Q&As, 40–65 words each ✓ - Total: ~650 words (target 450–650) ✓
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.