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 Weight Loss: UK Prescription Medication Guide
Carrying excess weight around the abdomen is linked to increased health risks, including type 2 diabetes and cardiovascular disease. In the UK, several prescription weight management medications are now available to help eligible adults lose weight effectively. This guide explains your options, how to find out if you qualify, and how prescription weight loss medication works alongside diet and exercise. Understanding what's available through the NHS and privately can help you make an informed decision about your weight management journey.
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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 Weight Loss Medications for Abdominal Weight Loss
Three prescription-only medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide).
Mounjaro is a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks when combined with dietary changes and exercise. Wegovy is a once-weekly GLP-1 injection, with clinical data showing average weight loss of approximately 15% of body weight. Saxenda is a daily injection also licensed for weight management.
To be eligible for prescription weight loss medication in the UK, you typically need a BMI of 30 or above, or a BMI of 27–29.9 with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). Use our free BMI calculator to check your starting point. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have access at lower BMI thresholds due to higher health risks at lower weights.
Individual results vary significantly. These medications work best alongside a reduced-calorie diet and increased physical activity—they are not replacements for lifestyle changes.
Clinically BackedWeight Loss
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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: Your Route to Weight Loss Treatment
In the UK, you can access prescription weight loss medication through two routes. NHS access is through specialist tier 3 weight management services following a referral from your GP. However, availability varies significantly by region, and waiting times can be lengthy in many areas. Private access is available through GPhC-registered online prescribing services, where a UK-licensed prescriber conducts a clinical assessment and issues a prescription if appropriate, typically without waiting lists.
To find out if you're eligible, start by speaking with your GP about your weight management goals and health concerns. Your GP can refer you to local NHS weight management services, discuss whether prescription medication may be suitable, and advise on the best route for your circumstances. You can also use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses, and our progress tracker to monitor your weight management journey once you've started 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.
What is abdominal weight loss medication?
Prescription weight loss medications licensed in the UK include Mounjaro, Wegovy, and Saxenda. These are GLP-1 (and GIP/GLP-1) receptor agonist injections that help reduce appetite, support feeling fuller after smaller meals, and may help you lose weight when combined with diet and exercise. They are prescription-only and require a clinical assessment before use.
Am I eligible for weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes or high blood pressure. Eligibility is assessed on an individual basis. Speak to your GP about NHS specialist weight management services in your area, though waiting times vary significantly by region.
How much weight can I lose with these medications?
Clinical trials showed average weight loss of 15–21% of body weight over several months when used alongside a reduced-calorie diet and exercise. Individual results vary significantly. Some people lose more, some less—weight loss depends on many factors including your starting weight, adherence, and lifestyle changes.
What's the difference between NHS and private prescription weight loss treatment?
NHS access is through specialist services following a GP referral, but availability and waiting times vary by region. Private access is available through online prescribing services without a referral, typically faster, but at a cost. Both routes require a clinical assessment and prescription from a UK-licensed prescriber.
Are there side effects I should know about?
Common side effects include nausea, diarrhoea, vomiting, and constipation, particularly during dose increases. These often reduce over time. Serious side effects are rare but can include severe stomach pain or gallbladder problems. Your prescriber will discuss potential side effects and monitor you during treatment.
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.