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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Smelly Burps on Mounjaro — Why It Happens and How to Manage It
Smelly or foul-tasting burps are a reported side effect that some people experience when taking Mounjaro (tirzepatide). This happens because Mounjaro slows how quickly food moves through your stomach, which can lead to increased gas production and changes in how your digestive system processes food. While not everyone experiences this, understanding why it occurs and knowing your options can help you manage it effectively. If you're considering Mounjaro or currently taking it, it's helpful to know both the side effect profile and the cost implications of accessing this medication in the UK.
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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.
Understanding Smelly Burps on Mounjaro and UK Access Routes
Why smelly burps occur on Mounjaro: Mounjaro slows gastric emptying (how quickly food leaves your stomach), which can cause fermentation and gas buildup. This may lead to unpleasant-smelling burps, especially if you eat fatty or high-fibre foods. The effect typically improves as your body adjusts to the medication over several weeks.
Managing the side effect: Eating smaller meals more frequently, avoiding fatty and overly processed foods, staying hydrated, and taking gentle walks after eating can reduce gas production. Some people find that ginger tea or peppermint helps with digestion. If the symptom persists beyond 4–6 weeks, discuss it with your prescriber — dose adjustments or timing changes may help.
Accessing Mounjaro in the UK: You can obtain Mounjaro through two main routes: NHS specialist weight management services (subject to eligibility and regional availability) or private online prescription services. Understanding the cost differences between these routes is important when deciding which is right for you.
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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
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UK Cost and Access: NHS vs Private Routes for Mounjaro
NHS access: If prescribed through an NHS specialist tier 3 weight management service, Mounjaro is free on the NHS. However, access is limited and eligibility requires referral from your GP, a BMI of 30+ (or 27+ with weight-related health conditions), and availability in your region. Many areas have significant waiting lists.
Private access: Through GPhC-registered online pharmacies, private Mounjaro prescriptions typically cost £129–£240 per month depending on your dose. The dose titration schedule starts at 2.5mg and escalates weekly over 16+ weeks to reach the maximum 15mg dose. Calculate your likely dosing stage using our free GLP-1 weight loss calculator to understand potential costs across your treatment journey.
What's included: Private prescriptions cover the clinical assessment, the prescription itself, and the Mounjaro KwikPen. You may also access support resources and dose escalation guidance from your 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.
Is Mounjaro available on the NHS for weight loss in the UK?
Yes, Mounjaro is available through NHS specialist tier 3 weight management services for eligible adults. Eligibility requires a BMI of 30+ or 27+ with weight-related health conditions. However, NHS availability varies significantly by region and waiting lists can be lengthy. Your GP can refer you to your local specialist service.
What does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£240 per month depending on your dose. Starting doses (2.5mg) are usually cheaper than maintenance doses (15mg). Costs may vary between private prescribing services, so it's worth comparing. Our GLP-1 weight loss calculator can help you estimate costs at different dose levels.
Why do some people get smelly burps on Mounjaro?
Mounjaro slows stomach emptying, which can cause gas and fermentation of food. This leads to unpleasant-smelling burps, especially after fatty meals. The side effect often improves within 4–6 weeks as your body adjusts. Eating smaller meals, staying hydrated, and avoiding very fatty foods can help reduce symptoms.
How long does Mounjaro dose titration take in the UK?
Mounjaro dose titration typically takes 16+ weeks to reach the maximum 15mg dose. You start at 2.5mg and increase by one dose level every 4 weeks if well tolerated. Your prescriber will guide the schedule based on how you respond and any side effects you experience.
Can I switch from Wegovy to Mounjaro on the NHS or privately?
Switching between GLP-1 medications requires your prescriber's guidance and clinical reassessment. Some NHS services may switch if one medication isn't suitable, though this varies by region. Privately, you can discuss switching with your prescriber after clinical review. Both tirzepatide (Mounjaro) and semaglutide (Wegovy) are available in the UK through both NHS specialist services and private routes.
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.