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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Mounjaro and Statins — What You Need to Know
If you're taking a statin for cholesterol management and considering Mounjaro (tirzepatide) for weight management, it's important to understand how these medications work together. Statins lower cholesterol, while Mounjaro is a prescription GLP-1 and GIP receptor agonist designed to support weight loss. Both are commonly prescribed in the UK, and many patients take them safely together. However, your GP or prescriber needs to assess your individual situation before starting Mounjaro to ensure it's appropriate for you. This guide explains the relationship between these two medications and what to expect.
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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 Statins Interact
The good news: Mounjaro and statins can generally be used together safely. Mounjaro does not directly interact with statin medications like atorvastatin, simvastatin, or rosuvastatin. However, there are important considerations to understand.
Mounjaro works by activating GLP-1 and GIP receptors, which help regulate appetite and blood sugar. Statins work through a completely different mechanism — they reduce the production of cholesterol in the liver. Because they work on different biological pathways, there is no direct pharmacological interaction between them.
That said, Mounjaro may slow how quickly oral medications are absorbed by slowing gastric emptying (how quickly food leaves your stomach). This effect typically reduces over time as your body adjusts. Your GP or prescriber should be aware of all medications you're taking, including statins, when assessing your suitability for Mounjaro. If you're already on a statin, mention this during your clinical assessment. Your prescriber may monitor your cholesterol levels more closely during treatment, as weight loss itself can improve cholesterol profiles.
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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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Mounjaro vs Wegovy — How They Compare
When considering weight management medications, you may hear about both Mounjaro (tirzepatide) and Wegovy (semaglutide). Both are prescription-only injections licensed in the UK, and both can be used alongside statins. The key difference is their mechanism: Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only.
Clinical trial data shows Mounjaro may produce slightly greater average weight loss (15–21% of body weight) compared to Wegovy (approximately 15%), though individual results vary significantly. Neither medication has direct interactions with statins. Your prescriber will decide which medication is more suitable for you based on your personal health profile, medical history, and individual needs — not on which one is "better" in general. Both require a clinical assessment before prescription.
- 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.
Can I take Mounjaro if I'm already on a statin?
Yes, Mounjaro and statins can generally be used together safely. They work through different mechanisms and do not directly interact. However, inform your GP or prescriber of all medications you're taking. They may monitor your cholesterol levels during treatment, as weight loss itself can improve cholesterol profiles.
Will Mounjaro affect how my statin works?
Mounjaro does not change how statins work chemically. However, Mounjaro may slightly slow the absorption of oral medications by slowing gastric emptying. This effect typically diminishes over time. Your prescriber can assess whether any adjustments are needed based on your individual situation.
Should I stop my statin before starting Mounjaro?
No — do not stop your statin without your GP's guidance. Continue taking your statin as prescribed. Inform your prescriber that you're on a statin during your Mounjaro clinical assessment. They will advise whether any changes are needed.
How does Wegovy compare to Mounjaro if I'm on a statin?
Both Mounjaro and Wegovy can be used safely alongside statins. Neither has direct interactions with statin medications. Wegovy is a GLP-1 agonist only, while Mounjaro is a dual GIP and GLP-1 agonist. Clinical trial data suggests Mounjaro may produce slightly greater average weight loss, but individual results vary. Your prescriber will recommend the most suitable option for you.
Will weight loss from Mounjaro affect my cholesterol levels?
Weight loss itself often improves cholesterol profiles, including LDL cholesterol. If you lose weight with Mounjaro, your GP may monitor your cholesterol levels and potentially adjust your statin dose. This is a positive outcome and shows the medication is supporting your overall health. Discuss any changes with your GP.
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