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
Free tracker included with every download this week
Sulphur Burps and Mounjaro — What You Need to Know
Sulphur burps are a reported side effect of Mounjaro (tirzepatide) that some people experience during treatment. While not everyone has this symptom, understanding what causes it and how to manage it can help you decide if Mounjaro is right for you. This guide covers the side effect itself, why it happens, practical management strategies, and the UK cost and access options for getting Mounjaro through NHS specialist services or private prescription. Whether you're considering this dual GIP and GLP-1 receptor agonist injection or already taking it, we'll help you understand the full picture.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Understanding Sulphur Burps as a Mounjaro Side Effect
Sulphur burps—formally called eructation with a rotten egg or sulphur smell—occur because Mounjaro slows how quickly food moves through your stomach and intestines (gastric emptying). This slower digestion can allow bacterial fermentation of food, producing hydrogen sulphide gas with a distinctive sulphur smell. In clinical trials and real-world use, sulphur burps are reported by a subset of Mounjaro users, though they're not assured and severity varies widely.
Prevalence and timing: Sulphur burps tend to be more common in the first few weeks of starting Mounjaro or after dose increases, as your body adjusts. Many people find the symptom improves or disappears over time as tolerance builds. They're also more likely if you eat fatty, protein-heavy, or difficult-to-digest foods.
Management strategies: Eating smaller, more frequent meals; avoiding greasy or high-fat foods; staying hydrated; and taking time between eating and lying down can help reduce episodes. Some users report that ginger tea, peppermint, or digestive enzymes offer relief. If sulphur burps persist or significantly affect quality of life, your prescriber may adjust your dose or suggest additional support.
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.
Mounjaro Access and Cost in the UK — NHS vs Private Routes
NHS access: Mounjaro is approved by NICE for use within the NHS, but availability is limited to specialist tier 3 weight management services. Your GP can refer you, though waiting lists vary significantly by region and can extend to many months. Once approved, NHS treatment is free at point of use.
Private prescription route: You can access Mounjaro privately through an online consultation with a UK-licensed prescriber. A GPhC-registered pharmacy then dispenses the Mounjaro KwikPen following your prescription. Private costs typically range from £129 to £320 per month depending on the dose you're on—lower doses (2.5–5 mg) are less expensive than maintenance doses (10–15 mg). The online consultation fee is usually £30–£50 and is often credited against your first prescription. Unlike Wegovy, direct price comparison across providers is less standardised, so checking multiple clinics is wise.
- 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.
Are sulphur burps a common side effect of Mounjaro in the UK?
Sulphur burps are reported by some Mounjaro users but are not listed as a "very common" or "common" side effect in the official product information. They occur because tirzepatide slows stomach emptying, allowing food fermentation. Severity and frequency vary widely between individuals—some experience them briefly when starting, others not at all.
Can I manage sulphur burps without stopping Mounjaro?
Yes. Most people find sulphur burps improve over time as the body adjusts. Management includes eating smaller, frequent meals; avoiding fatty foods; staying hydrated; and taking digestive support like ginger or peppermint. If they persist severely, discuss with your prescriber about dose adjustment rather than stopping entirely.
How much does Mounjaro cost in the UK through private prescription?
Private Mounjaro costs range from approximately £129–£320 per month depending on dose and provider. Starting doses (2.5–5 mg) are cheaper; maximum doses (15 mg) more expensive. Online consultations cost £30–£50 and may be credited against your first prescription. NHS treatment is free but access is through specialist services with variable waiting times.
What's the difference between Mounjaro and Wegovy in terms of side effects?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Both can cause gastrointestinal side effects including nausea and diarrhoea, but the specific profile differs slightly. Sulphur burps appear more commonly reported with Mounjaro, though individual experiences vary.
Do I need a prescription to buy Mounjaro in the UK?
Yes. Mounjaro is prescription-only in the UK. You must have a clinical assessment from a UK-licensed prescriber (either through NHS referral to specialist services or via private online consultation) before a pharmacy can dispense it. No legitimate pharmacy supplies Mounjaro without a valid prescription.
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.