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
Feeling Bloated on Mounjaro? What You Need to Know
Bloating is one of the most common side effects reported by people taking Mounjaro (tirzepatide) in the UK. This happens because the medication slows how quickly food moves through your stomach, which can initially cause digestive discomfort including gas, bloating, and abdominal pain. The good news is that bloating typically improves within the first few weeks as your body adjusts to the medication. Understanding what causes this side effect, how to manage it, and what Mounjaro costs in the UK can help you make an informed decision about treatment.
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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.
Bloating on Mounjaro: Causes, Duration, and Management in the UK
Bloating occurs because Mounjaro works partly by slowing gastric emptying — the rate at which food leaves your stomach. This delayed digestion can trap gas and food in your digestive system, creating discomfort. This effect typically diminishes over time as your body adapts, usually within 2–4 weeks, though some people experience it longer depending on dose and individual factors.
To manage bloating while taking Mounjaro, try eating smaller, more frequent meals, drinking plenty of water, avoiding carbonated drinks and high-fat foods, and incorporating gentle movement like walking. If bloating persists beyond the first month or becomes severe, speak to your prescriber — they may adjust your dose or suggest additional support. Bloating is not dangerous, but it can be uncomfortable, and your healthcare team can help.
Our GLP-1 weight loss calculator above can help you explore what results might be realistic with Mounjaro treatment, and our BMI calculator helps you understand your current health baseline before starting medication.
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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.
Mounjaro Cost and Access in the UK: NHS vs Private Routes
In the UK, accessing Mounjaro depends on whether you use the NHS or private route. NHS access is through specialist tier 3/4 weight management services — you'll need a GP referral and assessment. Availability varies significantly by region and waiting lists can be long. Private prescription access is faster: you have an online clinical consultation with a UK-licensed prescriber, and if approved, your prescription is dispensed by a GPhC-registered pharmacy. Private Mounjaro typically costs £120–£280 per month depending on your dose, ranging from 2.5 mg (starting dose) up to the maximum 15 mg weekly injection. Costs include the medication and clinical support. Always compare providers and ensure you're using a legitimate, regulated UK service — never buy from unlicensed sellers.
- 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.
How long does bloating last when taking Mounjaro?
Bloating typically improves within 2–4 weeks as your body adjusts to the medication slowing your digestion. However, some people experience it longer depending on their individual response and dose. If bloating persists beyond 4 weeks or worsens, contact your prescriber for guidance.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £120–£280 per month, depending on your dose (2.5 mg to 15 mg weekly). This usually includes the medication and prescriber support. NHS access is free but requires referral to a specialist weight management service and may involve waiting lists.
Can I get Mounjaro (tirzepatide) through the NHS in the UK?
Yes, Mounjaro is NICE-approved for NHS use through specialist tier 3/4 weight management services. You'll need a GP referral and assessment. Regional availability varies significantly, and waiting times can be months to years in some areas.
What's the difference between Mounjaro and Wegovy for bloating?
Both are GLP-1-based medications that slow digestion and can cause bloating. Mounjaro is a dual GIP+GLP-1 agonist; Wegovy is GLP-1 only. Clinical trial data suggests similar bloating rates, though individual experiences vary. Your prescriber will help choose the best option for you.
Should I stop taking Mounjaro if I'm bloated?
No — bloating is usually temporary and manageable. Try dietary adjustments like smaller meals and avoiding carbonated drinks. Contact your prescriber before stopping; they can assess whether your dose needs adjusting or if additional support would help.
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.