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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Stomach Fat Weight Loss — Prescription Medication Options in the UK
Stomach fat — also called visceral fat — sits around internal organs and poses particular health risks. If you're looking to lose weight and reduce belly fat, prescription weight management options are now available in the UK for eligible adults. This guide covers NHS and private prescription medications, who can access them, and how they work alongside diet and exercise to support weight loss and improve health outcomes.
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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 Stomach Fat Reduction
Three prescription medications are currently licensed in the UK for weight management:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 receptor agonist, once-weekly injection. Clinical trials showed participants lost an average of 15–21% of body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — GLP-1 receptor agonist, once-weekly injection. STEP trial data showed average weight loss of approximately 14.9% at 68 weeks on the maximum dose.
- Saxenda (liraglutide) — GLP-1 receptor agonist, once-daily injection. May help reduce appetite and support sustainable weight management.
All three are prescription-only and work by activating natural appetite-regulating hormones. Individual results vary significantly. These medications are most effective when combined with dietary changes and increased physical activity. A prescriber will assess whether weight loss medication uk options are suitable for your individual health profile.
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 and How to Find Out If You're Eligible
Eligibility criteria: Adults with a BMI of 30 kg/m² or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease) may be considered. For South Asian, Black African, Black Caribbean, or Chinese adults, lower BMI thresholds apply due to higher health risks at lower weights.
NHS access: Specialist tier 3 weight management services can prescribe these medications. Referral from your GP is required. Availability and waiting times vary significantly by region.
Private access: Available through GPhC-registered online prescribing services following a clinical assessment. No NHS referral needed. Use our GLP-1 weight loss calculator to explore projected outcomes at different doses. Talk to your GP about nhs weight management support or whether private options are appropriate for you.
Calculate your personal BMI using our free BMI calculator above to understand your starting point. Even a 5–10% reduction in body weight can significantly improve health markers including blood pressure, blood sugar control, and cholesterol levels. Weight loss medications are tools that work alongside lifestyle changes — not replacements for them. Your GP or a licensed prescriber can discuss whether prescription weight loss medication is right for you, considering your medical history, current medications, and personal health goals. The NHS recommends losing weight at a sustainable rate of 0.5–1 kg per week. Track your progress over time using our free progress tracker to monitor both weight changes and how you feel as you work towards your targets.
- 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 visceral fat and why is it a health concern?
Visceral fat sits around internal organs in the abdomen and poses greater health risks than subcutaneous fat under the skin. Higher visceral fat is linked to increased risk of type 2 diabetes, heart disease, and metabolic syndrome — regardless of overall BMI. Weight loss, particularly through prescription glp-1 weight loss medication combined with diet and exercise, can help reduce visceral fat stores.
How quickly can I expect to lose stomach fat with prescription weight loss medication?
Clinical trials show average weight loss of 15–21% over several months, though individual results vary significantly. Results depend on starting weight, dose, adherence to medication, dietary changes, and activity level. Most people experience gradual loss over weeks and months rather than rapid change. Consult your prescriber about realistic timelines for your situation.
Are weight loss injections safe for long-term use?
Mounjaro and Wegovy are approved for ongoing weight management in eligible adults. Like all medications, they carry potential side effects — commonly nausea, diarrhoea, and constipation, which often reduce over time. Serious side effects are rare. Your prescriber will monitor your health and discuss ongoing suitability. Pregnancy must be avoided during treatment.
Can I get these medications on the NHS, and what's the waiting time?
Yes, but access is through specialist tier 3 weight management services by GP referral. Availability and waiting times vary widely by region — some areas have waits of months to years. Private prescription options are available without NHS referral. Ask your GP about local NHS weight management services and discuss whether private or NHS access is appropriate for you.
What's the difference between Mounjaro and Wegovy for stomach fat weight loss?
Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1 only. Clinical data suggests Mounjaro may produce slightly greater average weight loss (15–21% vs ~15%), though individual responses vary. Both are once-weekly injections. Cost, availability, and personal tolerability differ. Your prescriber will discuss which is more suitable based on your health profile and local access.
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.