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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Abdominal Fat Weight Loss: UK Medication Options
Abdominal fat is often the most stubborn area to lose weight, but prescription weight management medication is now available in the UK for eligible adults. If you're struggling with excess weight around your midsection, understanding your options for weight management UK through NHS and private routes can help you take the next step. This guide explains what prescription weight loss medications are available, who can access them, and how to start a conversation with your GP.
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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: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Mounjaro and Wegovy are once-weekly injections, whilst Saxenda is a daily injection.
These GLP-1 weight loss medications work by activating natural hormone pathways that help regulate appetite and support feeling fuller after smaller meals. Clinical trials have shown promising results: in trials, Mounjaro participants lost an average of 15–21% of their body weight, whilst Wegovy participants lost approximately 15% on average—though individual results vary significantly and depend on the dose used, alongside dietary changes and increased physical activity.
Eligibility for prescription weight loss medication typically requires a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to increased health risks at lower weights. Our BMI calculator can help you check your current category and understand your starting point.
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.
Accessing Weight Loss Medication: NHS vs Private
In the UK, prescription weight loss medication can be accessed through two routes: NHS specialist services or private online prescribing.
NHS access: Your GP can refer you to a tier 3 specialist weight management service, where you'll receive a comprehensive assessment. However, availability varies significantly by region, and waiting lists can be lengthy—sometimes many months to over a year. Once approved, the NHS typically prescribes the most cost-effective option first.
Private access: GPhC-registered online pharmacies offer prescription weight loss medication following an online clinical assessment with a UK-licensed prescriber. This route is typically faster and doesn't require a GP referral, though costs range from approximately £130–£320 per month depending on dose and provider.
Whether you choose NHS or private, start by speaking to your GP about whether prescription weight loss medication is suitable for you. They can discuss your health, assess eligibility, and help you understand the best route forward.
- 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.
Can prescription weight loss medication specifically target abdominal fat?
Prescription GLP-1 medications support overall weight loss rather than targeting specific areas. However, research suggests that visceral fat (deep abdominal fat) is often lost preferentially during weight loss. Individual results vary based on genetics, diet, exercise, and the medication dose used. Use our GLP-1 weight loss calculator to estimate potential results.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are prescription-only injections taken once weekly. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with clinical trial results showing 15–21% average weight loss. Wegovy (semaglutide) is a GLP-1 agonist showing approximately 15% average weight loss. Your prescriber will recommend the most suitable option based on your health profile.
How long does it take to see weight loss results with prescription medication?
Most people notice initial changes within 4–8 weeks, though significant weight loss typically becomes apparent over 3–6 months. The medication works best alongside a reduced-calorie diet and increased physical activity. Results are individual and depend on dose, adherence, and lifestyle factors.
Will my GP prescribe weight loss medication on the NHS?
Your GP can refer you to an NHS tier 3 specialist weight management service if you meet eligibility criteria (BMI 30+ or 27+ with health conditions). However, NHS prescription availability varies greatly by region. Ask your GP about local services and waiting times, or explore private options for faster access.
Is it safe to use prescription weight loss medication long-term?
These medications have been used safely in clinical practice for several years. Your prescriber will monitor your progress regularly and adjust doses as needed. Common side effects include nausea and digestive changes, which often improve over time. Always report any concerns to your healthcare 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.