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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gradual weight management After Going Gluten-Free: UK Health Guide
Going gluten-free can lead to gradual weight management, especially in the first few weeks. This happens for several reasons: reduced calorie intake, less bloating and water retention, and improved digestion in people with coeliac disease or gluten sensitivity. However, gradual weight management isn't always healthy or sustainable. If you've experienced significant weight changes or are looking to manage your weight more effectively, prescription weight management options are now available in the UK for eligible adults. Understanding your BMI and health status is the first step.
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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 Options Available in the UK
If you're looking to manage your weight loss safely and sustainably, the UK now has three licensed prescription medications for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide).
Mounjaro is a once-weekly injection that works by activating two hormone pathways, helping reduce appetite and support feeling fuller. In clinical trials, participants lost an average of 15–21% of their body weight over 72 weeks alongside diet and exercise.
Wegovy is also a once-weekly GLP-1 injection, with average weight loss of around 15% in clinical trials. Saxenda is a daily injection option with similar effectiveness.
All three are prescription-only medicines and require a clinical assessment to confirm eligibility. Your BMI, health conditions, and personal circumstances determine suitability. Many UK adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions, may qualify.
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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 Access vs Private: How to Find Out Your Options
NHS access: Weight loss medications are available through specialist tier 3 weight management services, typically accessed via GP referral. However, availability and waiting times vary significantly by region. Some areas have lengthy waits of several months or longer.
Private access: If NHS access isn't available quickly in your area, you can access prescription weight loss medication through a UK-licensed online prescriber. Following a clinical assessment, if appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy.
Whichever route you choose, discuss your weight loss goals and health history with your GP first. They can assess your eligibility and advise whether prescription support is right for you. Calculate your BMI using our free BMI calculator above to understand your starting point.
- 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.
Is gradual weight management after going gluten-free dangerous?
Rapid initial weight loss (first 2–4 weeks) is often due to reduced water retention and bloating, not fat loss, and is generally not dangerous. However, if weight loss continues rapidly beyond that (more than 1–2kg weekly), or you feel unwell, contact your GP. Sustainable weight loss is typically 0.5–1kg per week.
Can I use prescription weight loss medication if I'm gluten-free?
Yes. Prescription medications like Mounjaro and Wegovy work regardless of diet. However, they work best alongside a reduced-calorie diet and increased physical activity. Your prescriber will assess your overall health and eligibility during a clinical assessment.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro is a dual GIP and GLP-1 agonist (activates two hormone pathways), while Wegovy is a GLP-1-only agonist. Clinical trials showed Mounjaro produced average weight loss of 15–21%, slightly higher than Wegovy's 15%. Individual results vary significantly.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, or cardiovascular disease). Lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP can assess eligibility.
Should I try to lose more weight without medication first?
That depends on your health status and how much weight you need to lose. A GP or specialist can advise. Many people find prescription weight loss medication helpful alongside lifestyle changes. Use our GLP-1 weight loss calculator to see potential outcomes with medication, and discuss with your GP whether it's appropriate for you.
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.