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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Mounjaro Wind and Burping vs Wegovy: What's the Difference?
Wind and burping are common digestive side effects reported by people taking weight loss injections. If you're considering Mounjaro (tirzepatide) or Wegovy (semaglutide) for weight management in the UK, understanding how these medications differ in their mechanisms and potential side effects can help you and your GP make an informed decision. Both are prescription-only GLP-1-based medications, but they work slightly differently, which may influence digestive symptoms. This guide compares the two based on clinical trial data and UK prescribing context.
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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 Mounjaro and Wegovy Work Differently
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist—it activates two hormone pathways simultaneously. This dual mechanism may affect gut motility and gastric emptying differently compared to single-pathway medications. In the SURMOUNT clinical trials, gastrointestinal side effects including nausea, diarrhoea, and abdominal discomfort were reported in the majority of participants across all doses.
Wegovy (semaglutide) is a GLP-1-only receptor agonist—it targets a single hormone pathway. The STEP clinical trials showed similar gastrointestinal side effects, though some prescribers report that the dose titration schedule (starting at 0.25 mg and escalating slowly) may allow the body more time to adjust.
- Mounjaro starts at 2.5 mg weekly and escalates every 4 weeks
- Wegovy starts at 0.25 mg weekly over a 17-week escalation period
- Slower dose escalation may reduce initial digestive symptoms for some people
- Individual responses vary significantly—some experience minimal symptoms, others experience more
The dual-mechanism approach of Mounjaro may theoretically affect gastric motility more intensely than Wegovy's single pathway, but clinical trial data does not show a clear superiority of one over the other for digestive side effects specifically.
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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.
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Which Medication Might Be Right for You?
Wind and burping are typically temporary and often reduce as your body adjusts to the medication during the first 4–8 weeks. Both Mounjaro and Wegovy are prescription-only and require a clinical assessment before being prescribed. Your GP or a licensed prescriber will assess your individual health profile, medical history, and any previous medication reactions to determine which is most suitable.
Try our free GLP-1 weight loss calculator above to understand projected weight loss at different doses—this can help you discuss realistic expectations with your prescriber. Use our BMI calculator to establish your starting point, and consider tracking digestive symptoms with our progress tracker if you do begin treatment, as this information helps your prescriber adjust your dose if needed.
If you experience severe or persistent wind, burping, or other gastrointestinal symptoms, contact your prescriber immediately—dose adjustment or temporary pause may be recommended. Never stop or change your dose without medical guidance.
- 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 wind and burping worse with Mounjaro than Wegovy?
Clinical trial data does not show clear superiority of one over the other for digestive symptoms specifically. Mounjaro's dual mechanism may affect gastric motility differently, but individual responses vary widely. Your prescriber can help determine which is more suitable based on your medical history and any previous medication reactions.
How long does wind and burping last on these medications?
Digestive side effects, including wind and burping, typically peak in the first 2–4 weeks and often improve by week 8 as your body adjusts. Some people experience minimal symptoms; others find them persistent. Dose titration—starting low and increasing gradually—can help. Contact your prescriber if symptoms remain severe.
Can I reduce wind and burping by changing my diet?
Yes. Eating slowly, chewing thoroughly, avoiding carbonated drinks and high-fat foods, and staying hydrated may help reduce gas and bloating. Ginger tea or peppermint may provide relief for some people. Your GP or a dietitian can suggest personalised dietary adjustments alongside your medication.
What's the difference between Mounjaro and Wegovy?
Mounjaro is a dual GIP and GLP-1 agonist; Wegovy is GLP-1-only. Mounjaro's maximum dose is 15 mg weekly; Wegovy's is 2.4 mg weekly. Both are once-weekly injections licensed for weight management in UK adults. Clinical trials show both support weight loss alongside diet and exercise—individual suitability is determined by your prescriber.
Do I need a prescription for Mounjaro or Wegovy in the UK?
Yes, both are prescription-only medicines. In the UK, you can access them through NHS specialist weight management services (tier 3) via GP referral, or privately through a GPhC-registered pharmacy following an online clinical assessment with a UK-licensed prescriber.
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