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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Does Mounjaro Cause Wind? Mounjaro vs Wegovy Comparison
Wind and bloating are common questions about GLP-1 and GIP/GLP-1 medications. Both Mounjaro (tirzepatide) and Wegovy (semaglutide) can cause gastrointestinal side effects including wind, bloating, and stomach discomfort, particularly when starting treatment or during dose increases. The frequency and severity vary between individuals and between the two medications. Understanding the differences can help you and your prescriber decide which option might be more suitable for your circumstances. This guide compares both medications based on clinical trial data and UK prescribing guidance.
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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.
Mounjaro vs Wegovy: Gastrointestinal Side Effects
Both Mounjaro and Wegovy are prescription-only GLP-1 receptor agonist injections (Mounjaro is technically a dual GIP+GLP-1 agonist) and both can cause gastrointestinal effects including wind, bloating, indigestion, and stomach pain. In clinical trials, these side effects were very common—affecting more than 1 in 10 people.
Mounjaro (tirzepatide): The SURMOUNT trial showed nausea, diarrhoea, vomiting, constipation, and abdominal pain were very common. Wind and bloating may occur, particularly in the first 4–8 weeks. Side effects often improve as the body adjusts to the tirzepatide medication.
Wegovy (semaglutide): The STEP trials reported similar gastrointestinal effects including nausea, diarrhoea, vomiting, constipation, and stomach pain. Wind and indigestion occur frequently, especially during dose titration. Effects typically reduce over time as tolerance develops.
The dual mechanism of Mounjaro (GIP + GLP-1) may slow stomach emptying differently than Wegovy's single GLP-1 mechanism, potentially affecting bloating patterns in some users—though individual variation is significant.
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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.
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Which Medication Might Suit You Better?
Choosing between Mounjaro and Wegovy depends on individual factors that only a prescriber can assess. Your GP or a licensed prescriber will consider your medical history, current medications, gastrointestinal tolerance, BMI, and any weight-related health conditions like type 2 diabetes or high blood pressure.
If you experience significant wind or bloating with one medication, switching to the other is sometimes possible—but this requires prescriber guidance. Practical strategies like eating slowly, avoiding carbonated drinks, and taking smaller meals often help reduce wind regardless of which UK prescription medication you use.
Both Mounjaro and Wegovy require a prescription and clinical assessment. Use our free GLP-1 weight loss calculator to explore potential outcomes, and discuss side effect management with your prescriber before starting treatment.
- 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.
Does Mounjaro cause more wind than Wegovy?
Both medications can cause wind and bloating, but individual experiences vary widely. Mounjaro's dual GIP+GLP-1 mechanism may affect stomach function differently than Wegovy's single GLP-1 action. Clinical trial data shows similar rates of gastrointestinal side effects for both. Your prescriber can help determine which might suit you better based on your medical profile.
How long does wind and bloating last on Mounjaro?
Gastrointestinal side effects like wind and bloating are typically most pronounced in the first 4–8 weeks, particularly during dose titration. Many people find symptoms improve significantly after 8–12 weeks as the body adjusts. If side effects persist beyond this, discuss with your prescriber—dose adjustment or switching medications may help.
Can I reduce wind while taking Mounjaro or Wegovy?
Yes. Practical strategies include eating slowly and mindfully, avoiding carbonated beverages, reducing high-fat foods, eating smaller frequent meals, and staying hydrated. Some people find ginger tea or peppermint helpful. If wind persists, inform your prescriber—they may adjust your dose or suggest alternative medications. Both require UK prescription and clinical assessment.
Is wind a sign Mounjaro isn't working?
No. Wind and bloating are common side effects of GLP-1 and GIP/GLP-1 medications and do not indicate whether the medication is effectively supporting weight loss. These gastrointestinal effects are separate from the medication's weight management action. Your prescriber monitors both side effects and weight loss progress during treatment.
Should I stop Mounjaro or Wegovy if I have wind?
Do not stop without prescriber guidance. Wind is a common but usually temporary side effect that often improves with time. Stopping abruptly may affect your treatment plan. Always discuss persistent side effects with your GP or prescriber—they may adjust your dose, suggest management strategies, or consider switching to an alternative prescription medication.
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