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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How Do You Stop Mounjaro — What You Need to Know
Stopping Mounjaro (tirzepatide) should always be managed with your GP or prescriber — it's not something to stop abruptly without medical guidance. Unlike some medications, GLP-1 and dual GIP/GLP-1 agonists like Mounjaro can cause rebound appetite and weight regain if stopped without a plan. If you're considering stopping Mounjaro, or wondering how it compares to Wegovy for your situation, this guide covers stopping safely, what to expect, and how the two medications differ in terms of discontinuation and mechanism.
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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 to Stop Mounjaro Safely — Stopping vs Wegovy Comparison
Stopping Mounjaro should always be discussed with your prescriber first. Unlike some medications, you cannot simply stop Mounjaro without consequences — appetite typically returns quickly, and weight regain is common within weeks if no lifestyle plan is in place.
How to stop Mounjaro safely:
- Speak to your GP or the prescriber managing your Mounjaro — do not stop without guidance
- Finish your current KwikPen — do not discard half-used pens
- Plan a gradual transition: strengthen diet and exercise habits before stopping
- Expect appetite to return to baseline within days to weeks
- Your prescriber may recommend transitioning to another medication or lifestyle management
Wegovy comparison: Wegovy (semaglutide) works via the same GLP-1 pathway as Mounjaro's GLP-1 component, though Mounjaro adds a dual GIP mechanism. Both show similar rebound effects when stopped — appetite returns and weight regain is common without ongoing lifestyle changes. Stopping either medication requires the same structured approach with your prescriber.
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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.
Rebound Appetite and Weight Regain — What the Research Shows
Clinical data shows that weight regain typically begins within 2–4 weeks of stopping GLP-1 or GIP/GLP-1 medications. This is not a failure — it reflects the natural return of appetite-regulating hormones to baseline. Your body is not broken; the medication was helping suppress appetite signals.
Studies show that adults who stop Mounjaro or Wegovy without establishing strong lifestyle habits tend to regain 50% of lost weight within 6 months. Those with structured diet and exercise plans regain weight more slowly. Your prescriber or a dietitian can help you build a realistic transition plan. Use our free GLP-1 weight loss calculator to explore what ongoing support might look like, and our progress tracker to maintain accountability as you adjust.
- 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 stop Mounjaro immediately, or do I need to taper it?
Mounjaro does not require a medical taper like some medications — you finish your current dose and then stop. However, discuss stopping with your prescriber first to plan for appetite return and weight regain. Stopping "cold turkey" without a lifestyle plan often results in rapid weight regain.
What's the difference between stopping Mounjaro and stopping Wegovy?
Both medications are GLP-1 receptor agonists (Mounjaro also has GIP activity) and both show similar rebound effects when stopped. Appetite returns and weight regain is common. Stopping either requires a structured plan with your prescriber — no medical difference in discontinuation safety.
How quickly will my appetite return after stopping Mounjaro?
Appetite typically begins returning within days to one week of your last injection. It may reach baseline within 2–4 weeks. This is normal and expected — your body's natural hunger signals are returning. Your prescriber can advise on managing this transition.
What should I do to prevent weight regain when stopping Mounjaro?
Before stopping, work with your prescriber or a dietitian to strengthen diet and exercise habits. Continue calorie-conscious eating, increase physical activity, and plan ongoing support. Our progress tracker can help you monitor weight during the transition period.
Is there an alternative if I need to stop Mounjaro?
Your prescriber may suggest transitioning to another GLP-1 medication like Wegovy, continuing with lifestyle management alone, or exploring other NHS tier 3 weight management options. This decision depends on your individual health, eligibility, and response to treatment.
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.