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 Give You Wind?
Yes, wind (bloating and gas) can occur when taking Mounjaro, though it's not listed as a very common side effect in the official UK prescribing information. Mounjaro (tirzepatide) is a prescription-only GLP-1 and GIP receptor agonist used for weight management in UK adults. Many people report experiencing digestive changes including wind, constipation, and diarrhoea, particularly during the initial weeks of treatment or when increasing your dose. The good news is that these symptoms often improve over time as your body adjusts to the medication. If you're concerned about side effects, your GP or the prescriber managing your treatment can provide personalised advice.
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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.
How Does Mounjaro Affect Digestion?
Mounjaro works by activating two hormone pathways — GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 — which help regulate appetite and food intake. One of the ways it does this is by slowing gastric emptying, meaning food moves through your stomach more slowly than usual. This delayed digestion can cause several digestive side effects including wind, bloating, indigestion, and constipation or diarrhoea. These effects are particularly common in the first few weeks of treatment or when moving to a higher dose during your dose titration schedule.
- Slowed stomach emptying: Food lingers longer, fermentation increases, causing gas
- Altered gut bacteria: Dietary changes may shift your microbiome temporarily
- Dietary sensitivity: Fatty or rich foods may be less well tolerated initially
- Dose-related: Side effects often reduce as your body adapts, usually within 2–4 weeks
The NHS notes that gastrointestinal side effects like wind are among the most commonly reported experiences with GLP-1 and GIP/GLP-1 medications, but they are typically mild to moderate and temporary.
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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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Managing Wind and Bloating on Mounjaro
If you experience wind or bloating while taking Mounjaro, several practical strategies may help. Eat slowly and chew food thoroughly, avoid carbonated drinks and high-fat meals, and increase your water intake. Some people find that smaller, more frequent meals cause less bloating than larger portions. Keep a food diary to identify which foods trigger symptoms — common culprits include fatty or fried foods, high-fibre foods consumed too quickly, and artificial sweeteners. If symptoms persist beyond 4 weeks or significantly affect your quality of life, contact your prescriber or GP. They may adjust your dose, suggest dietary modifications, or in rare cases, review whether the medication remains appropriate for you. Remember to use our free GLP-1 weight loss calculator to track your progress and discuss any side effects with your healthcare team.
- 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 a common side effect of Mounjaro?
Wind and bloating are not listed as "very common" side effects in UK prescribing data, but many people report experiencing them, particularly in the first few weeks or during dose increases. These symptoms often improve as your body adjusts. If you're concerned, discuss with your prescriber.
How long does Mounjaro-related wind last?
Most digestive side effects, including wind, tend to improve within 2–4 weeks as your body adapts to the medication. However, some people experience longer-term changes in digestion. Individual experiences vary significantly.
Can I reduce wind by changing what I eat?
Yes. Avoiding carbonated drinks, fatty foods, and high-fibre foods consumed too quickly may help. Eating smaller meals slowly and chewing thoroughly can also reduce gas. Keep a food diary to identify your personal triggers.
Should I stop taking Mounjaro if I get wind?
No — do not stop without speaking to your prescriber first. Wind is usually temporary and manageable. Your GP or prescriber can suggest dietary changes or other strategies before considering any changes to your medication.
Is wind on Mounjaro different from Wegovy?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) can cause digestive side effects including wind, as both slow gastric emptying. Individual responses vary, and some people tolerate one better than the other. Your prescriber can discuss which may suit you.
Ready to take control of your weight loss journey?
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