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 and Coeliac Disease — What You Need to Know
If you have coeliac disease and are struggling with weight management, you're not alone. Many people with coeliac disease find weight loss challenging due to gut health, nutrient absorption, and metabolic factors. Once you've established a gluten-free diet and your gut has healed, your GP can help you explore safe weight loss options. For eligible adults with a BMI of 30 or above (or 27 or above with weight-related health conditions), prescription weight loss medication is now available through the NHS or private clinics. This guide covers how weight management works with coeliac disease and what treatment options exist in the UK.
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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.
Prescription Weight Loss Medication Available in the UK
Three prescription-only weight loss injections are currently licensed in the UK for eligible adults. All require a clinical assessment before being prescribed.
- Mounjaro (tirzepatide) — a once-weekly dual GIP and GLP-1 receptor agonist. In clinical trials, participants lost an average of 15–21% of their body weight alongside dietary changes and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 receptor agonist. Clinical trials showed average weight loss of around 15% of body weight over 68 weeks.
- Saxenda (liraglutide) — a once-daily GLP-1 injection. Offers similar weight loss support to Wegovy.
All three medications work by reducing appetite, helping you feel fuller after smaller meals, and slowing how quickly food leaves your stomach. For people with coeliac disease, these can be particularly helpful because they reduce overall food intake while your gut continues to heal. Individual results vary significantly, and weight loss medication works best alongside a balanced gluten-free diet, increased physical activity, and support from your healthcare team.
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 Treatment — NHS or Private Route
NHS route: Your GP can refer you to a specialist tier 3 weight management service, where a healthcare team will assess your eligibility and overall health. NHS access is free but availability varies by region, and waiting times can be several months.
Private route: You can arrange a private online consultation with a UK-licensed prescriber. A clinical assessment is carried out, and if appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy. This typically costs £129–£320 per month depending on the dose.
Either way, your GP should be informed of any weight loss treatment you're considering. They can also help monitor your progress and ensure the medication doesn't interact with any other health conditions or medications you take.
- 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 coeliac disease?
Yes, if you're eligible by BMI and have a clinical assessment. However, your GP needs to know about your coeliac disease because it may affect nutrient absorption and how your body responds to medication. Ensure your gut is stable on a gluten-free diet before starting any new treatment. Your prescriber will consider your overall health profile.
Does GLP-1 medication interfere with a gluten-free diet?
No. GLP-1 medications like Mounjaro and Wegovy don't interfere with gluten-free foods or your coeliac disease. They work by reducing appetite and food intake. Continue your gluten-free diet exactly as before — the medication simply helps you eat smaller, manageable portions while maintaining nutritional intake.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You're eligible if you have a BMI of 30 or above, or 27 or above with at least one weight-related health condition (such as high blood pressure, type 2 diabetes, or sleep apnoea). Use our free BMI calculator to check your BMI instantly. A GP or prescriber will assess your individual health status and suitability.
Will weight loss medication help if my weight gain is related to coeliac disease?
If your weight gain occurred before diagnosis or during poor gut health, healing your gut with a strict gluten-free diet is the first step. Once your gut has stabilised and you've been gluten-free for several months, prescription medication can support additional weight loss if needed. Work with your GP and gastroenterologist to ensure both conditions are managed together.
What's the difference between NHS and private weight loss medication?
Both use the same prescription medications (Mounjaro, Wegovy, Saxenda) and require clinical assessment. NHS access is free but involves waiting for specialist referral (varying timescales by region). Private access is faster but costs £129–£320/month. Both routes are legitimate; your choice depends on urgency and preference.
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.