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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Can I Take Mounjaro If I've Had My Gallbladder Removed?
If you've had your gallbladder removed and are considering Mounjaro (tirzepatide) for weight management, it's important to understand how this affects your eligibility. Mounjaro may still be an option for you, but it requires careful assessment by a healthcare professional. This guide explains what you need to know about taking this prescription-only injection after gallbladder surgery, and why your medical history matters when your GP or prescriber evaluates whether it's suitable for you.
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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.
Mounjaro and Gallbladder Removal — What You Need to Know
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that may help support weight management when used alongside a reduced-calorie diet and increased physical activity. One of Mounjaro's effects is that it slows gastric emptying — meaning food moves more slowly from your stomach into your small intestine. This action is particularly relevant if you've had your gallbladder removed, because bile (which helps digest fat) is no longer released in response to eating.
- Without a gallbladder, bile flows continuously rather than on demand, which some people find affects digestion, particularly of fatty foods
- Mounjaro's effect of slowing stomach emptying may compound digestive changes you already experience post-surgery
- This doesn't necessarily mean you cannot take Mounjaro, but it does mean your prescriber needs to assess the risk versus benefit for your individual situation
- Your prescriber will review your complete medical history, including gallbladder surgery, before issuing a prescription
Always inform your GP or prescriber about any previous abdominal surgery, including cholecystectomy (gallbladder removal), when requesting weight management treatment.
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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.
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What Your Prescriber Will Consider
When assessing your suitability for Mounjaro following gallbladder removal, your prescriber will evaluate several factors. These include how long ago your surgery was, whether you've experienced ongoing digestive issues, and whether you currently take any medications that might interact with tirzepatide. If you've had significant post-cholecystectomy symptoms — such as persistent diarrhoea, fat malabsorption, or chronic abdominal discomfort — your prescriber may recommend alternative weight loss options or suggest additional monitoring if Mounjaro is prescribed.
Your GP can provide personalised advice and refer you to a specialist weight management service (tier 3 NHS services) if needed. You can also use our free GLP-1 weight loss calculator to explore what weight loss outcomes might look like with different medications, and our BMI calculator to check where your current weight sits on NHS guidelines.
- 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.
Will Mounjaro cause gallbladder problems if I've already had my gallbladder removed?
No — without a gallbladder, you cannot develop gallbladder disease. However, Mounjaro may affect your existing digestion patterns because it slows stomach emptying. Your prescriber will assess whether this is safe for you based on your post-surgery symptoms and overall health.
Can I take Mounjaro if I had my gallbladder removed years ago?
Possibly, yes. Time since surgery can matter — if you've fully recovered and have no ongoing digestive complications, your prescriber may consider Mounjaro suitable. Recent surgery or persistent symptoms may mean alternatives are safer. This requires individual assessment.
What should I tell my prescriber about my gallbladder removal?
Inform them of the date of your surgery, why it was removed (gallstones, inflammation, etc.), and whether you've experienced lasting digestive changes. Mention any current symptoms like diarrhoea, constipation, or fat intolerance. This information helps them assess suitability accurately.
Are there other weight loss injections I can take after gallbladder removal?
Possibly — Wegovy (semaglutide) and Saxenda (liraglutide) are alternative GLP-1 injections licensed for weight management in the UK. Each has different mechanisms and side effect profiles. Your prescriber can discuss which option is safest for your medical history.
How do I access Mounjaro or alternatives if I've had gallbladder surgery?
Start by discussing weight management options with your GP. You can be referred to NHS tier 3 specialist weight management services, or you can access prescription weight loss treatment privately through a UK-licensed online prescriber following a clinical assessment. Both routes require medical evaluation of your gallbladder surgery history.
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.