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 to Safely Stop Taking Mounjaro in the UK
If you've been taking Mounjaro (tirzepatide) and want to stop, it's important to do so safely and with guidance from your prescriber. This guide covers NHS recommendations, what to expect when you stop, and how to maintain weight loss after discontinuation. Never stop suddenly without speaking to your GP or the healthcare professional managing your treatment — they can advise on the safest approach for your individual 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.
How to Stop Mounjaro Safely and When to Speak to Your GP
Do not stop Mounjaro suddenly without medical guidance. If you decide to discontinue, inform your prescriber — whether through NHS tier 3 specialist services or your private online prescriber — as soon as possible. Your GP or prescriber may recommend gradually reducing your dose rather than stopping immediately, though some people do stop at their current dose and simply skip the next injection.
Common reasons for stopping include:
- Persistent or intolerable side effects (especially nausea, constipation, or diarrhoea)
- Gallbladder or pancreatic issues
- Pregnancy or planning pregnancy
- Financial reasons (private prescriptions can cost £150–£320 per month depending on dose)
- Achieving weight loss goals and feeling ready to maintain independently
- Switching to a different weight management approach or medication
Your prescriber will discuss the safest way to discontinue based on your medical history and how long you've been taking the medication.
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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
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What Happens to Your Weight After Stopping Mounjaro
Weight regain is common after stopping any weight loss medication if lifestyle changes aren't maintained. Clinical data suggests many people regain some weight within months of discontinuing GLP-1 or tirzepatide treatment, though the amount varies significantly between individuals. To help prevent rapid weight regain:
- Continue a reduced-calorie diet — don't suddenly increase food intake
- Maintain regular physical activity (NHS recommends 150 minutes of moderate exercise weekly)
- Track your progress using a food diary or our free progress tracker
- Stay hydrated and prioritise protein at meals
- Consider ongoing support from a dietitian or weight management service
Some NHS tier 3 weight management services offer ongoing support after medication stops, so discuss this with your prescriber before discontinuing.
- 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 gain weight back immediately after stopping Mounjaro?
Not necessarily immediately, but weight regain often begins within weeks if diet and exercise habits aren't maintained. The hormone effects wear off quickly (tirzepatide is cleared from your body within days), so appetite typically returns to normal. How much you regain depends on whether you maintain the reduced-calorie diet and physical activity you developed while on the medication. Your GP can discuss strategies to minimise regain.
Can I restart Mounjaro if I stop and regain weight?
Potentially, yes — but this depends on your prescriber and whether you remain eligible. If you stopped through NHS tier 3 services, you'd need to be reassessed and re-referred. If you were taking it privately, your prescriber can advise whether restarting is appropriate. Discuss your weight loss goals and concerns with your GP or prescriber before stopping, as they may recommend a phased approach instead of full discontinuation.
What should I do about my diet after stopping Mounjaro?
Continue eating the reduced-calorie, balanced diet you've been following while on Mounjaro. Don't suddenly increase portion sizes or return to old eating habits, as this is when weight regain happens most rapidly. Consider asking your GP for a referral to a dietitian or weight management service for ongoing support. Use our free BMI calculator and progress tracker to monitor your weight and help keep you accountable after stopping.
Is it safe to stop Mounjaro cold turkey?
While there's no specific withdrawal risk, stopping suddenly without medical guidance isn't recommended. Your appetite may return quickly and significantly, making it harder to maintain weight loss. Your prescriber may suggest a gradual approach — for example, extending the time between injections rather than stopping immediately. Always contact your GP or prescriber first before making any changes to your medication.
What are the UK prescription costs if I restart Mounjaro later?
Private tirzepatide prescriptions in the UK typically cost £150–£320 per month depending on your dose. NHS access is free but requires specialist tier 3 referral and may involve waiting lists. If you're considering stopping due to cost, discuss this openly with your GP — they may be able to help you access NHS specialist services or discuss alternative options. Never stop a prescription medication for financial reasons without consulting your healthcare provider first.
Ready to take control of your weight loss journey?
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