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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Sulfur Burps on Mounjaro — UK Access and Cost Information
Sulfur burps (belching with a rotten egg smell) are a documented side effect that some people experience while taking Mounjaro (tirzepatide) for weight management. If you're considering this prescription medication in the UK, it's important to understand not just the potential side effects, but also how to access Mounjaro and what it costs through both NHS and private routes. This guide covers everything you need to know about accessing tirzepatide in the UK and managing expectations around cost and availability.
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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.
How Much Does Mounjaro Cost in the UK and Where Can You Access It?
Mounjaro access in the UK differs significantly between NHS and private routes. NHS access is through specialist tier 3 weight management services following a GP referral — availability and waiting times vary dramatically by region and local ICB (Integrated Care Board). Some areas have multi-month waiting lists; others may not currently offer tirzepatide at all. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Private costs typically range from £129 to £320 per month depending on your dose, with a standard Mounjaro KwikPen (4 weeks of injections) costing approximately £150–£280 privately. The dose you're prescribed affects cost — starting doses (2.5mg) are cheaper than maximum doses (15mg). Unlike some medications, Mounjaro costs remain consistent across UK private providers because the medication itself is the same; differences reflect consultation and dispensing fees. If you're interested in exploring potential outcomes, our free GLP-1 weight loss calculator can help you estimate projected weight loss at different Mounjaro doses before committing to treatment.
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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 Route vs Private Route — Which Is Right for You?
NHS route: Free once prescribed, but requires GP referral to specialist services and can involve lengthy waits. Private route: Faster access (usually within 1–2 weeks), no NHS waiting lists, but you pay for consultations and medication. The online consultation process for private Mounjaro involves completing a health questionnaire, a licensed prescriber reviewing your medical history and BMI, and if approved, a prescription being issued to a UK pharmacy. You'll need to be eligible (BMI ≥30 or ≥27 with weight-related health conditions) and declare any medications or conditions. Check your personal BMI using our free BMI calculator above to confirm your eligibility before starting the consultation process. Both routes require the same clinical criteria — the difference is speed, cost, and whether you're assessed by the NHS or a private prescriber.
- 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 exactly are sulfur burps, and why do they happen on Mounjaro?
Sulfur burps are belches with a rotten egg smell caused by hydrogen sulfide gas in the digestive system. On Mounjaro, they occur because tirzepatide slows gastric emptying (how quickly food leaves the stomach), allowing food to ferment longer in the stomach. This fermentation produces sulphurous gases. The effect typically reduces over time as your body adjusts, though some people experience it throughout treatment.
Can I get Mounjaro on the NHS, and if so, how long is the wait?
Yes, Mounjaro (tirzepatide) is approved for NHS specialist weight management services following NICE guidance. Access requires a GP referral to your local tier 3 weight management service. Waiting times vary by region from a few weeks to over a year depending on local availability and demand. Contact your GP for a referral if you meet eligibility criteria (BMI ≥30 or ≥27 with comorbidities).
How much does Mounjaro cost privately in the UK?
Private costs typically range from £129–£320 per month depending on your dose. A standard KwikPen (4 weeks supply) costs approximately £150–£280 privately. Starting doses are cheaper than maximum doses. You'll also pay for the online consultation (usually £30–£80), though some providers include this in the medication price. Total first-month cost is typically £180–£360.
What happens during an online consultation for private Mounjaro?
You'll complete an online health questionnaire covering your medical history, current medications, height, weight, and BMI. A UK-licensed prescriber reviews your information to assess eligibility and safety. If approved, a prescription is issued to a GPhC-registered pharmacy, which dispenses your Mounjaro. The entire process typically takes 3–7 days from consultation to receiving your medication at home.
Is Mounjaro the same as Wegovy, and which is cheaper in the UK?
No — Mounjaro (tirzepatide) and Wegovy (semaglutide) are different medications. Mounjaro is a dual GIP and GLP-1 receptor agonist; Wegovy is a GLP-1 agonist only. Both are available privately in the UK at similar price points (£129–£320/month depending on dose). Availability and cost can vary slightly between providers and dose strengths. Your prescriber will assess which is more suitable for you based on your health profile.
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.