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
Mounjaro Trapped Wind vs Wegovy — What's the Difference?
Trapped wind, bloating, and digestive discomfort are common side effects of both Mounjaro (tirzepatide) and Wegovy (semaglutide) in the UK. Both are prescription-only weight loss injections that work on the GLP-1 pathway, but they have different mechanisms and may affect digestive systems differently. Understanding how each medication works and what clinical trial data shows about these specific side effects can help you and your prescriber decide which option might be more suitable for your individual circumstances.
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.
How Mounjaro and Wegovy Differ in Mechanism and Side Effects
Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways, which may explain why some users report more pronounced gastrointestinal effects including trapped wind and bloating. Wegovy is a GLP-1 receptor agonist only, activating a single pathway, which may result in a different side effect profile.
In clinical trials, both medications caused common digestive side effects like nausea, diarrhoea, and constipation. Trapped wind and abdominal discomfort were reported in clinical data for Mounjaro (SURMOUNT trial) and Wegovy (STEP trials). However, individual experiences vary significantly. Some people on Mounjaro report more bloating, whilst others tolerate it better than Wegovy. The dose also matters — higher doses typically cause more pronounced gastrointestinal effects. Both medications slow gastric emptying (how quickly food leaves the stomach), which can contribute to trapped wind and bloating, particularly during dose titration.
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.
Which Medication Might Be Better for Trapped Wind Concerns?
Neither Mounjaro nor Wegovy is assured to cause less trapped wind — it depends entirely on your individual physiology and how your body responds. Your prescriber will assess your medical history, current medications, and any existing digestive conditions before recommending one over the other.
If you have a history of gastroparesis (stomach paralysis) or severe digestive issues, your GP may be cautious about either medication. Both require a clinical assessment before prescription in the UK. If trapped wind becomes a significant problem once you're taking either medication, contact your prescriber — dose adjustment, spacing of meals, or dietary changes may help. In some cases, digestive symptoms improve over time as your body adjusts to the medication, though this varies. Use our free BMI calculator and GLP-1 weight loss calculator to understand your eligibility and projected outcomes, then discuss any digestive concerns with your prescriber during your clinical assessment.
- 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 trapped wind than Wegovy?
Clinical trial data doesn't show clear superiority for either medication regarding trapped wind specifically. Mounjaro's dual mechanism may cause more pronounced gastrointestinal effects for some people, but individual responses vary significantly. Trapped wind during dose titration is common with both medications and often improves over time.
Can I switch from Mounjaro to Wegovy if I get trapped wind?
Yes, switching is possible if your prescriber agrees. However, trapped wind is a common early side effect of both medications and often resolves as your body adjusts. Before switching, discuss with your prescriber whether managing the symptom (diet, spacing meals) or adjusting your dose might be more appropriate first.
How long does trapped wind last on these medications?
Gastrointestinal side effects, including trapped wind and bloating, are typically most pronounced during dose escalation (the first 4–8 weeks). Many people find symptoms improve significantly after 8–12 weeks as their body adapts. However, individual timelines vary — some experience persistent mild bloating throughout treatment.
Are there any dietary changes that help with trapped wind on Mounjaro or Wegovy?
Yes. Eating slowly, chewing thoroughly, avoiding high-fat and high-fibre foods initially, staying hydrated, and eating smaller, more frequent meals can all reduce trapped wind. Because these medications slow stomach emptying, large meals are particularly problematic. Your GP or a registered dietitian can provide personalised guidance.
Which medication is better if I have a sensitive stomach?
Neither medication is inherently "better" for sensitive stomachs. Both require clinical assessment and should only be prescribed if your GP believes the benefits outweigh digestive risks. If you have a known history of IBS, gastroparesis, or severe reflux, inform your prescriber — they may recommend closer monitoring or suggest Wegovy's once-daily dosing alternative (Saxenda) instead.
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.