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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Can You Stop and Start Mounjaro?
Yes, you can stop and restart Mounjaro (tirzepatide), but it requires careful management by your prescriber. Mounjaro is a prescription-only weight loss injection, and any decision to pause, stop, or restart treatment should be discussed with your GP or the healthcare professional who prescribed it. Stopping abruptly without guidance may affect your weight management progress, and restarting involves specific considerations around dosing and timing. This guide explains what you need to know about stopping and restarting Mounjaro in the UK.
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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 Stopping Mounjaro Works
Stopping Mounjaro is possible, but there are several important considerations. Mounjaro works as a dual GIP and GLP-1 receptor agonist, meaning it helps regulate appetite and support feeling fuller after meals. When you stop taking it, these effects gradually reduce over days to weeks. Your prescriber may recommend tapering your dose gradually rather than stopping abruptly, particularly if you have been on a high dose like 15 mg. This can help minimise the return of appetite and reduce the risk of rapid weight regain. If you stop Mounjaro, your weight loss results are not permanent—weight loss achieved is typically maintained only while continuing the injection alongside dietary changes and increased physical activity. Some people stop temporarily for medical reasons, planned pregnancy, or personal circumstances. Your prescriber will assess whether it's safe for you to pause treatment based on your individual health situation, any other medications you take, and your weight management goals.
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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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Restarting Mounjaro — Dose and Timing
If you restart Mounjaro after stopping, you do not automatically resume at your previous dose. Your prescriber will reassess you and typically restart at the starting dose of 2.5 mg, then escalate gradually over weeks—the same titration schedule as initial treatment. This is because your body's tolerance to the medication resets during the break. The time between stopping and restarting matters: if you've been off Mounjaro for several weeks or months, restarting is usually a UK pharmacy as a fresh course. However, if you've only missed one or two weekly injections, your prescriber may allow you to resume at your current dose. Discuss your specific situation with your prescriber—never assume you can restart at the same dose independently. Using our GLP-1 weight loss calculator can help you understand projected outcomes once you restart treatment at your new dose.
- 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.
What happens to weight loss if I stop Mounjaro?
Weight loss achieved while on Mounjaro is typically maintained only while continuing treatment alongside diet and exercise. If you stop, appetite regulation returns to baseline and weight regain is common. Studies show most people regain weight within months of stopping. Your prescriber can discuss long-term strategies with you.
Can I stop Mounjaro suddenly or do I need to taper?
While stopping suddenly is not dangerous, your prescriber may recommend gradually reducing your dose, especially from higher doses like 15 mg. Gradual tapering can help minimise appetite return and reduce metabolic shock. Always discuss stopping plans with your prescriber rather than stopping without guidance.
Do I restart Mounjaro at the same dose if I stop and restart?
No. If you restart after stopping, you typically begin again at 2.5 mg and titrate gradually, regardless of your previous highest dose. Your body's tolerance resets during the break. Your prescriber will confirm the restart schedule based on how long you've been off treatment.
How long can I safely pause Mounjaro treatment?
Short breaks (one or two missed injections) are manageable and can be resumed at your current dose. Longer breaks of several weeks or months are a UK pharmacy as restarting treatment, requiring dose titration from 2.5 mg. Discuss any planned pause with your prescriber beforehand to ensure it's safe for you.
Is it safe to stop Mounjaro if I'm planning pregnancy?
Mounjaro is not recommended during pregnancy, and you should stop at least 4 weeks before attempting conception. Discuss fertility plans with your GP or prescriber—they can advise on timing and alternative weight management strategies during this period. Your prescriber may recommend a specific stopping protocol.
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.