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
When Should You Stop Taking Mounjaro?
Deciding when to stop Mounjaro is a personal decision that should always be made in consultation with your prescriber. Some people stop after reaching their goal weight, while others continue long-term to maintain results. There's no set timeline — stopping depends on your individual health goals, how well the medication is working, and whether side effects are manageable. Your GP or prescriber will help you decide what's right for your situation.
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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 People Stop Mounjaro and What Your Prescriber Will Consider
There are several reasons why someone might decide to stop their Mounjaro prescription. Reaching your goal weight is one — if you've achieved the weight loss you wanted, stopping may be discussed. Side effects can also prompt stopping; if nausea, diarrhoea, or other effects become intolerable despite dose adjustments, your prescriber may recommend discontinuing. Some people stop due to cost, especially if using private prescription. A small number experience gallbladder problems or other serious side effects that require stopping.
Your prescriber will also consider: whether weight loss has plateaued (if so, continuing may not help), how long you've been on treatment, and whether you've made sustainable lifestyle changes. Unlike some medications, Mounjaro doesn't require a gradual taper — you can stop it without a weaning period, as tirzepatide leaves your system within days.
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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 Happens to Your Weight After Stopping Mounjaro
After stopping Mounjaro, some weight regain is common — this happens because your appetite hormones return to baseline and the medication's effects wear off within 1–2 weeks. Research suggests that people who maintain the lifestyle changes they made while on Mounjaro (reduced-calorie diet, increased physical activity) experience less regain than those who don't.
If significant weight regain occurs, your prescriber may recommend restarting at a lower dose or exploring other options. Mounjaro can be restarted if needed. Some people use our GLP-1 weight loss calculator to project potential outcomes if they restart. Weight maintenance is a long-term process — stopping the medication doesn't erase progress made, but ongoing healthy habits are essential to sustaining results.
- 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 whenever I want?
Yes, you can stop Mounjaro at any time without a weaning period, as tirzepatide leaves your system quickly. However, discuss stopping with your prescriber first — they can help ensure you're ready and discuss strategies to maintain your weight loss through diet and lifestyle changes.
Will I regain all the weight I lost when I stop Mounjaro?
Not necessarily. Weight regain is common but varies by individual. People who maintain their reduced-calorie diet and increased physical activity tend to regain less weight than those who return to previous eating habits. Using a progress tracker can help you monitor changes after stopping.
How long after stopping Mounjaro will I feel hungry again?
Most people notice increased appetite within 1–2 weeks as tirzepatide clears the body and natural hunger hormones return. This is why maintaining lifestyle changes (smaller portions, regular meals, exercise) is crucial during this transition period.
Can I restart Mounjaro if I regain weight after stopping?
Yes, Mounjaro can be restarted if needed. Your prescriber will reassess your eligibility and may restart at the initial dose (2.5 mg) or adjust based on your response. Discuss with your GP if weight regain becomes a concern.
What's the difference between stopping Mounjaro and Wegovy?
Both are stopped the same way — without tapering — as both are GLP-1/GIP receptor agonists that clear quickly. The main difference is their mechanism: Mounjaro is a dual GIP/GLP-1 agonist while Wegovy is GLP-1 only. Weight regain patterns after stopping are similar for both.
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.