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
Can You Take Mounjaro If You've Had Your Gallbladder Removed?
If you've had your gallbladder removed and are considering Mounjaro (tirzepatide) for weight management, you'll need a clinical assessment from your prescriber to determine whether it's safe for you. Having your gallbladder removed doesn't automatically prevent you from using Mounjaro, but it does require careful medical consideration. Your prescriber needs to understand your individual health history to assess whether this GLP-1 and GIP receptor agonist injection is appropriate. This guide explains what you need to know before starting treatment.
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.
Gallbladder Removal and Mounjaro Safety
Mounjaro is a prescription-only weight management injection that works by activating GLP-1 and GIP receptor pathways to help regulate appetite and support weight loss. One of the known side effects of GLP-1 and GIP medications like Mounjaro is an increased risk of gallbladder problems, including gallstones and cholecystitis (gallbladder inflammation).
If you've already had your gallbladder removed (cholecystectomy), this changes the risk profile. Without a gallbladder, you cannot develop gallstones or gallbladder inflammation — the organ is no longer present. However, your prescriber still needs to assess your overall digestive health, because:
- Mounjaro slows gastric emptying, which may affect digestion differently in people who've had cholecystectomy
- Some people experience bile reflux or digestive changes after gallbladder removal
- Your liver function and bile production need evaluation
- Any history of pancreatitis (which can be linked to gallbladder disease) must be discussed
A UK-licensed prescriber will review your medical history, current medications, and post-surgical recovery status before deciding if Mounjaro is suitable for you.
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.
What Your Prescriber Needs to Know
When seeking a Mounjaro prescription, inform your healthcare provider about your cholecystectomy surgery, including when it was performed and the reason (gallstones, inflammation, etc.). This medical history helps your prescriber assess your individual risk and suitability for Mounjaro and tirzepatide treatment.
You should also discuss any digestive symptoms you've experienced since gallbladder removal — such as bile reflux, diarrhoea, or abdominal discomfort — as these may be relevant to how Mounjaro affects you. Your prescriber may want to check your liver function and ensure you've fully recovered from surgery before starting the injection. If you have a history of pancreatitis, this is particularly important to disclose, as GLP-1 medications carry a theoretical pancreatitis risk that requires careful evaluation in your UK prescription 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.
Is Mounjaro completely safe if I've had my gallbladder removed?
Having no gallbladder means you cannot develop Mounjaro-related gallbladder problems. However, your prescriber still needs to assess your individual digestive health, post-surgical recovery, and any related conditions like pancreatitis history. Safety depends on your complete medical picture, not just gallbladder removal alone.
Will my GP or private prescriber know about my cholecystectomy?
Your prescriber will ask about your full medical history as part of the clinical assessment. You must inform them of your gallbladder removal surgery. If using a private online prescriber, be thorough in your health questionnaire. If using NHS services, your GP records will include this information.
Can I use MyWeightCheck's GLP-1 weight loss calculator if I've had gallbladder surgery?
Yes — use our free GLP-1 weight loss calculator to explore potential weight loss projections with Mounjaro at different doses. This helps you understand the medication's possible effects, but any prescription decision must follow a proper clinical assessment with your actual prescriber.
How is Mounjaro different from Wegovy if I've had my gallbladder removed?
Both Mounjaro (tirzepatide — dual GIP and GLP-1 agonist) and Wegovy (semaglutide — GLP-1 only) carry similar gallbladder-related risks in people who still have a gallbladder. If yours is removed, both medications require prescriber assessment but are not automatically ruled out. Your prescriber will assess which is more suitable for your health profile.
What side effects of Mounjaro should I watch for after gallbladder removal?
Common Mounjaro side effects include nausea, diarrhoea, constipation, and stomach pain. Post-cholecystectomy, pay particular attention to digestive symptoms and report any severe or persistent abdominal pain to your GP immediately. Mounjaro comes as a pre-filled KwikPen and is injected once weekly — your prescriber will provide full guidance on use and monitoring.
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.