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 for Belly: UK Prescription Medication Options
Excess weight around the belly is linked to increased health risks, including type 2 diabetes and cardiovascular disease. If you're struggling with weight loss and have a BMI of 30 or above (or 27+ with weight-related health conditions), prescription weight management options are available through the NHS or private prescribing in the UK. These medications work alongside diet and exercise to support sustainable weight loss. This guide covers your options, eligibility, and how to get started.
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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 GLP-1 receptor agonist medications are currently licensed in the UK for weight management and can help with overall weight loss, including belly fat reduction:
- Mounjaro (tirzepatide) — A dual GIP and GLP-1 agonist injection, once weekly. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks. Maximum dose 15 mg.
- Wegovy (semaglutide) — A GLP-1 agonist injection, once weekly. Average weight loss approximately 15% of body weight in clinical trials. Maximum dose 2.4 mg.
- Saxenda (liraglutide) — A GLP-1 agonist injection, once daily. Similar clinical evidence to Wegovy. Maximum dose 3 mg daily.
All three work by reducing appetite, helping you feel fuller after smaller meals, and supporting weight management uk goals. Individual results vary, and these medications are most effective when combined with a reduced-calorie diet and increased physical activity. Try our GLP-1 weight loss calculator above to explore potential outcomes at different doses.
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.
Eligibility and How to Access Prescription Weight Loss in the UK
You may be eligible for prescription weight loss medication in the UK if you have a BMI of 30 kg/m² or above, or 27–29.9 with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply.
NHS access: Referral to a specialist tier 3 weight management service through your GP. Private access: Online consultation with a UK-licensed prescriber, available without NHS referral. Waiting times and costs vary by region and provider. Start by discussing your eligibility with your GP or exploring private options through registered online services.
Use our free BMI calculator above to check your current BMI and understand your starting point for weight management discussions.
- 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 help reduce belly fat specifically?
GLP-1 medications support overall weight loss, which typically includes reduction of visceral and subcutaneous fat. However, where your body loses fat first varies individually. Clinical evidence shows these medications help with overall weight management when combined with lifestyle changes, benefiting cardiovascular health and reducing diabetes risk.
What's the difference between NHS and private weight loss medication in the UK?
NHS access requires a GP referral to specialist services and involves assessments and longer waiting times. Private prescribing through registered online services offers faster access without NHS referral, but involves upfront costs (typically £150–£300+ monthly). Both pathways require clinical assessment and prescription from a UK-licensed prescriber.
How quickly will I lose weight on GLP-1 medication?
Weight loss varies by individual, medication, and dose. Clinical trials show average losses of 15–21% over several months to a year. The NHS recommends sustainable weight loss of 0.5–1 kg per week. Results depend on adherence to medication, diet changes, and activity level. Individual results vary significantly.
Are prescription weight loss injections available on the NHS for belly weight loss?
Yes, Mounjaro, Wegovy, and Saxenda are licensed on the NHS for eligible adults through specialist tier 3 weight management services. Access varies by region and availability. Your GP can refer you if you meet eligibility criteria. Private access is also available through registered UK prescribers without NHS referral.
What should I discuss with my GP about weight loss medication?
Discuss your current weight and BMI (use our free BMI calculator above), any weight-related health conditions, previous weight loss attempts, and your motivation. Ask about NHS referral eligibility, local specialist services, waiting times, and whether private options might be suitable. Your GP can assess whether prescription medication is appropriate for your individual health needs.
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.