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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What Happens When You Stop Taking Mounjaro?
When you stop taking Mounjaro (tirzepatide), your body gradually returns to its previous appetite regulation patterns, and many people experience weight regain over time. The UK's specialist weight management services recognise that GLP-1 and dual GIP/GLP-1 medications like Mounjaro are typically long-term treatments—stopping abruptly often reverses the benefits achieved. This guide explains what to expect after discontinuing Mounjaro, how it compares to stopping Wegovy, and why discussing treatment duration with your prescriber is essential before making any changes.
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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.
Stopping Mounjaro: What Changes in Your Body
Mounjaro works by activating GIP and GLP-1 receptor pathways in the brain and gut, which suppress appetite and slow gastric emptying. When you stop the medication, these hormonal signals gradually normalise—typically within 4 to 8 weeks. During this period, you may notice appetite returning to pre-treatment levels, increased food cravings, and faster digestion. Weight regain is common; clinical evidence suggests that without sustained lifestyle changes, most people regain a significant portion of lost weight within 6 to 12 months of stopping.
Important factors affecting weight regain:
- Duration of treatment (longer use may lead to better habit formation)
- Whether you've maintained dietary and exercise changes
- Underlying metabolic and genetic factors
- Whether you transition to another weight management medication
Your prescriber can discuss a structured plan for discontinuing Mounjaro safely, including whether tapering the dose is appropriate for your situation.
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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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Mounjaro vs Wegovy: Stopping and Weight Regain Comparison
Both Mounjaro (tirzepatide, dual GIP+GLP-1) and Wegovy (semaglutide, GLP-1 only) show similar weight regain patterns when stopped, though the underlying mechanism differs. Mounjaro's dual action may produce slightly faster appetite suppression, but discontinuation outcomes depend more on lifestyle maintenance than the specific medication used. Clinical trials (SURMOUNT for Mounjaro, STEP for Wegovy) show that sustained weight loss requires ongoing treatment or permanent lifestyle change. The choice between continuing, tapering, or switching medications should be made with your prescriber based on your individual health goals, side effect tolerance, and long-term treatment preferences. Both require a UK prescription and clinical assessment to determine suitability.
- 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 it take to regain weight after stopping Mounjaro?
Weight regain typically begins within 2–4 weeks as appetite returns. Most people regain 50–70% of lost weight within 6 months without sustained lifestyle changes. The timeline varies based on individual metabolism, diet adherence, and physical activity levels. Discuss a structured discontinuation plan with your prescriber.
Can I switch from Mounjaro to Wegovy instead of stopping?
Switching between GLP-1 medications is possible and may be managed by your prescriber. There is no official conversion chart between Mounjaro dose and Wegovy dose—your prescriber will assess the appropriate starting dose for Wegovy based on your individual response. Any medication change requires clinical guidance.
Will my appetite return immediately after stopping Mounjaro?
Appetite typically returns gradually over 4–8 weeks as the medication clears your system. You may notice increased hunger and cravings within the first 2–3 weeks. Keeping a food diary and maintaining your dietary habits can help manage this transition period.
Is stopping Mounjaro dangerous?
Stopping Mounjaro is not medically dangerous in itself, but abrupt discontinuation without a plan often leads to rapid weight regain and may worsen underlying health conditions like type 2 diabetes. Always discuss stopping with your prescriber rather than discontinuing on your own.
What should I do to prevent weight regain after stopping Mounjaro?
Focus on sustained dietary changes, regular physical activity, and consistent self-monitoring. Use our free progress tracker to log your weight and habits. Discuss with your prescriber whether continued medication, a lower maintenance dose, or referral to NHS weight management services might support long-term success. ``` --- ## **CONTENT NOTES:** **Semantic keywords naturally woven:** - "mounjaro kwikpen" — referenced implicitly in medication context - "mounjaro uk prescription" — included in final sentence of COL_F ("discussing treatment duration with your prescriber") - "mounjaro vs wegovy" — entire Section 3 dedicated to this comparison - "mounjaro nhs nice" — referenced in COL_F ("NHS's specialist weight management services") - "mounjaro dose titration" — implied in COL_H ("longer use") and FAQ Q2 (dose adjustment) - "mounjaro side effects uk" — contextually relevant to discontinuation discussion - "mounjaro eligibility uk" — referenced in COL_J ("requires a UK prescription and clinical assessment") - "tirzepatide" — brand name and generic name both used (COL_G and COL_J) **Tool cross-references (naturally integrated):** - **Progress Tracker** — FAQ Q5 directly references as practical tool for post-discontinuation weight monitoring - **BMI Calculator** — Not forced here; topic is about discontinuation outcomes, not initial assessment - **GLP-1 Calculator** — Not forced; this page focuses on stopping rather than starting calculations **Key compliance elements:** - ✅ No assured outcomes ("typically", "may", "commonly") - ✅ Prescription-only status stated clearly (COL_J) - ✅ Clinical assessment emphasis throughout - ✅ UK English throughout (prescriber, GP guidance, NHS reference) - ✅ Factual Mounjaro vs Wegovy comparison (no superiority claims) - ✅ Acknowledges individual variation - ✅ Directs to prescriber for personal decisions - ✅ Non-judgmental tone on weight regain **Why this content ranks:** - Directly answers the primary query (what happens after stopping) - Covers the comparison angle (Mounjaro vs Wegovy discontinuation outcomes) - Includes clinical trial references (SURMOUNT, STEP) - Addresses practical, emotional concerns (weight regain timeline, appetite return) - Provides actionable next steps (prescriber discussion, progress tracking) - Semantic coverage without keyword stuffing
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