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
What Happens When You Stop Mounjaro?
If you've stopped taking Mounjaro, you may be wondering what comes next. When you stop this prescription weight loss injection, your body gradually returns to its baseline appetite and metabolic patterns. Weight regain is common after stopping any weight loss medication, though the timeline and amount varies between individuals. This guide explains what to expect, why it happens, and what your options are. Always discuss stopping Mounjaro with your prescriber before making changes to your treatment.
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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.
Why Weight Regain Happens After Stopping Mounjaro
Mounjaro (tirzepatide) works by activating GIP and GLP-1 hormone pathways, which reduce appetite and help you feel fuller after smaller meals. When you stop the injection, these hormone effects gradually wear off over days to weeks. Your appetite returns to pre-treatment levels, and your body no longer has the medication's support for appetite control.
Weight regain is very common:
- Clinical trial data shows that people who stop GLP-1 medications typically regain weight gradually over months
- The amount regained varies — some people maintain most of their weight loss through lifestyle changes alone, while others regain significantly
- Regain usually happens over 3–6 months rather than all at once
- Your personal regain depends on whether you've maintained the reduced-calorie diet and increased physical activity that supported your initial weight loss
This is not a failure — it's how your body responds when the medication is removed. Many people find that the habits they built while on Mounjaro (smaller portion sizes, different food choices, movement habits) help slow regain considerably.
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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.
What to Do After Stopping Mounjaro
If you've stopped Mounjaro, the key is maintaining the lifestyle changes you developed while on it. Continue with reduced-calorie eating patterns, physical activity, and regular weighing if you find it motivating — try our free progress tracker to monitor your weight trend.
Talk to your GP or prescriber about:
- Why stopping was right for you at this time
- Whether you wish to restart Mounjaro or try an alternative like Wegovy (semaglutide)
- Support options such as NHS tier 3 weight management services or digital behaviour change programmes
- Whether continuing with lower-calorie eating and activity is achievable long-term for you
Some people restart Mounjaro after a break. Others transition to lifestyle management alone. Your prescriber can help you decide what suits your circumstances.
- 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 quickly do you regain weight after stopping Mounjaro?
Weight regain is typically gradual, occurring over 3–6 months rather than immediately. The speed and amount depends on whether you maintain your reduced-calorie diet and physical activity. Some people regain 30–50% of lost weight; others maintain most of their loss through lifestyle changes. Individual variation is significant.
Can you restart Mounjaro after stopping it?
Yes, Mounjaro can be restarted following a clinical assessment with your prescriber. If you stopped due to side effects, your prescriber may suggest starting at a lower dose or considering an alternative medication like Wegovy. If you stopped by choice, restarting follows the same process as initial prescription.
Is it normal to feel hungrier after stopping Mounjaro?
Yes, increased appetite is completely normal after stopping. Mounjaro suppresses appetite through GIP and GLP-1 pathways; when you stop, these effects gradually wear off over 1–2 weeks. Your appetite returning to baseline is expected and not abnormal.
What's the difference between Mounjaro and Wegovy after stopping?
Both are weight loss injections but work differently. Mounjaro (tirzepatide) is dual GIP+GLP-1; Wegovy (semaglutide) is GLP-1 only. Weight regain patterns after stopping are similar for both. Your prescriber can advise if switching is appropriate.
Should I try to maintain my weight loss after stopping Mounjaro?
Yes — maintaining your weight loss is much easier than losing it again. Focus on the eating and activity habits you developed while on Mounjaro. Calculate your healthy weight range using our free BMI calculator, then aim to stay within it using lifestyle methods. If you struggle, discuss restarting medication with your GP.
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.