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?
If you've stopped taking Mounjaro (tirzepatide), you may have questions about what comes next. It's normal to wonder whether weight will return, how quickly your body will adjust, and what alternatives might help. This guide explains what evidence shows happens after stopping this prescription injection, and how to manage your health going forward with support from your GP.
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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.
Weight Changes After Stopping Mounjaro
When you stop taking Mounjaro, your body gradually stops receiving the medication's effects on appetite regulation and blood sugar control. Weight regain is common, but it's important to understand this doesn't happen overnight. Clinical experience shows that without the medication's support, many people gradually return towards their previous weight over several months if lifestyle habits remain unchanged.
The rate of weight regain varies significantly between individuals. Some people maintain weight loss for months; others experience more rapid regain. This depends on factors including your diet, physical activity level, metabolism, and whether you've developed sustainable eating habits during treatment. Using our free GLP-1 weight loss calculator can help you understand what your weight trajectory might look like over time with or without medication support.
It's also common to notice increased appetite and food cravings returning within the first few weeks after stopping. This is because the medication's effect on your hunger hormones diminishes as it leaves your system. Your GP can discuss whether these changes are expected and whether continued support is needed.
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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.
Managing Your Health After Stopping — Key Steps
The most important step after stopping Mounjaro is to maintain the lifestyle habits you've developed — healthy eating patterns, regular physical activity, and stress management. Many people find these habits, once established, help prevent rapid weight regain even without medication.
Talk to your GP about your reasons for stopping and what happens next. They can offer support, suggest alternatives (such as Wegovy, which uses semaglutide rather than tirzepatide, or other weight management approaches), or monitor your weight and health markers over time. If you stopped due to side effects, discuss whether a different medication or approach might suit you better. Use the BMI calculator on this page to track your weight changes and identify any concerning patterns early.
Important Considerations and Next StepsIf you experienced side effects: Tell your GP exactly which side effects were problematic. Some improve with time or dose adjustment; others may mean this medication wasn't right for you. Alternatives exist.
If you stopped for personal reasons: Your GP can discuss whether returning to treatment might help, or whether lifestyle approaches alone are working for you.
If cost was the reason: Discuss NHS options. Mounjaro is available through NHS tier 3 specialist weight management services in some regions, though waiting lists vary significantly by area. Your GP can advise on eligibility and local services.
Regardless of your reason for stopping, maintaining regular contact with your healthcare team ensures you have support for your weight and overall health.
- 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 I definitely regain weight after stopping Mounjaro?
Weight regain is common but not assured. It depends on whether you maintain the lifestyle changes you've developed whilst taking the medication. Many people keep weight off for months or longer if diet and exercise habits remain consistent. Your GP can help you plan to minimise regain.
How quickly does Mounjaro leave your system?
Tirzepatide (the active ingredient in Mounjaro) has a half-life of about 4–5 days, meaning half the dose is eliminated roughly every 5 days. Most people stop experiencing appetite-suppressing effects within 2–3 weeks, though individual variation is significant.
Can I restart Mounjaro after stopping?
Yes, you can restart Mounjaro if you choose to and if your GP agrees it's appropriate. You would begin with the lowest dose again and titrate up. Discuss with your prescriber about the best approach for you, including whether the medication was working before you stopped.
What's the difference between Mounjaro and Wegovy if I want to switch?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Both are prescription-only weight management injections. Clinical trials show Mounjaro achieved slightly higher average weight loss, but individual results vary. Your GP or prescriber can advise which might suit you better.
Should I see my GP before stopping Mounjaro?
Yes, ideally. Your GP can discuss your reasons for stopping, check your health, and advise on whether weight management support or alternatives might help. If you've already stopped, contact your GP to review your progress and next steps.
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.