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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How to Stop Diabetic Weight Loss with UK Medication
If you're experiencing unwanted weight loss linked to diabetes, or you're looking to manage your weight effectively as a diabetic adult, prescription weight management medication may be an option worth discussing with your GP. The UK has several licensed medications designed to support weight management in adults with diabetes or related health conditions. This guide explains what's available, how they work, and how to find out if you're eligible for treatment through the NHS or private prescribing.
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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 Options for Diabetic Weight Management
Several prescription-only weight management injections are available in the UK for adults with diabetes or metabolic health concerns:
- Mounjaro (tirzepatide) — a once-weekly dual GLP-1 and GIP receptor agonist that may help regulate appetite and support weight loss. Clinical trials showed participants lost an average of 15–21% of their body weight alongside diet and activity changes.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection that may reduce food cravings and support feeling fuller after meals. Evidence suggests average weight loss of approximately 15% of body weight in clinical trials.
- Saxenda (liraglutide) — a daily GLP-1 injection, also licensed for weight management in the UK.
All three are prescription-only and require a clinical assessment before being prescribed. Your GP or a licensed prescriber will evaluate whether medication is suitable based on your individual health profile, diabetes status, and other factors. Use our GLP-1 weight loss calculator to explore potential weight loss projections at different doses, which may help inform your discussion with your prescriber.
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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 Next Steps
In the UK, you can access weight management medication through two routes:
- NHS — available through specialist tier 3 weight management services. Your GP can refer you, though waiting lists vary significantly by region and availability may be limited.
- Private — available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This route doesn't require an NHS referral.
To find out if you're eligible, start by speaking with your GP about your weight management goals and any diabetes-related concerns. They can assess whether prescription treatment is appropriate for you, discuss what weight loss means for your specific diabetes management, and explain both NHS and private options. Check your BMI using our free BMI calculator and note any weight-related health conditions — this information will be helpful in your conversation with your healthcare provider.
- 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 I take weight loss medication if I have type 2 diabetes?
Yes. Many adults with type 2 diabetes are eligible for prescription weight management medication. GLP-1 and GIP/GLP-1 medications are particularly suitable for diabetic patients because they help regulate blood sugar as well as support weight management. However, you may need dose adjustments to other diabetes medications, so prescriber assessment is essential.
What's the difference between Mounjaro and Wegovy for diabetics?
Mounjaro is a dual GIP and GLP-1 agonist; Wegovy is a GLP-1 agonist only. Both are prescription-only and licensed for weight management in the UK. Mounjaro showed slightly higher average weight loss in clinical trials (15–21% vs approximately 15%), but individual results vary. A prescriber will advise which suits your personal health profile.
How quickly will I lose weight on prescription medication?
Safe weight loss is typically 0.5–1 kg per week, though individual results vary significantly. Prescription medications are used alongside reduced-calorie diet and increased activity — medication alone won't produce results. Most people notice changes within 4–8 weeks, but it takes several months to reach maximum dose and see full benefits.
Will the NHS prescribe weight loss medication for me?
Potentially, yes — but NHS access is through specialist tier 3 weight management services, not standard GP prescription. You'll need a GP referral and usually meet specific BMI and health criteria. Availability and waiting times vary greatly by region. Your GP can check eligibility and waiting lists in your area.
What happens if I stop taking weight loss medication?
Weight typically returns over time if diet and activity don't change. These medications are meant to support long-term lifestyle change, not as a temporary fix. Your prescriber will discuss how long treatment should continue and what happens when you stop. Lifestyle changes made during treatment are key to maintaining weight loss.
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.