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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When To Stop Mounjaro: NHS Guidance for UK Adults
Deciding when to stop Mounjaro (tirzepatide) is a clinical decision that should always be made with your GP or prescriber, not independently. There is no fixed "stop date" — it depends on your individual health goals, weight loss progress, and how well you are tolerating the medication. In the UK, Mounjaro is prescribed through NHS specialist tier 3 weight management services or privately through licensed prescribers. This guide explains NHS guidance on discontinuation, what happens when you stop, and how to work with your healthcare team to make the right decision for your circumstances.
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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.
NHS Guidance on Mounjaro Discontinuation
There is no standard NHS protocol for when to stop Mounjaro — decisions are individualised based on clinical assessment. However, NICE and NHS guidance suggests several reasons why discontinuation might be considered:
- Weight loss goal achieved: If you have reached your target weight and demonstrated ability to maintain it, your prescriber may discuss stepping down or stopping.
- Tolerability issues: If side effects become intolerable despite dose adjustments, stopping may be appropriate.
- Medical contraindications: If new health conditions develop that make continued use unsafe (e.g., pregnancy planning, pancreatitis history, thyroid concerns).
- Lack of response: If after 12 weeks at an adequate dose there is minimal weight loss, continuing may not be evidence-based.
- Cost or access: On the NHS, continued prescribing depends on ongoing tier 3 specialist availability and regional ICB funding.
Unlike some medications, Mounjaro does not require a gradual tapering protocol — you can typically stop at any point without medical harm, though your prescriber should guide this.
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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 When You Stop Mounjaro
When you stop Mounjaro, several things typically happen. Appetite usually returns gradually over days to weeks as the medication leaves your system — the GIP and GLP-1 receptor agonist effects wear off. Weight regain is common if lifestyle changes (diet and physical activity) are not maintained; clinical data suggests most weight lost returns within months without ongoing behaviour support. Side effects resolve — nausea, constipation, and other GI symptoms typically improve within 1–2 weeks. Ongoing support is important — your GP or weight management service should provide maintenance advice, including access to a progress tracker to monitor changes, and behavioural strategies to prevent rapid rebound weight gain. The NHS recommends discussing a "maintenance plan" before stopping any weight loss medication.
- 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?
Mounjaro can be stopped at any time without needing to taper the dose — there is no medical harm in stopping immediately. However, you should not stop without discussing it with your prescriber first. Your GP or weight management service can help you plan discontinuation safely, discuss relapse prevention, and ensure you have ongoing support to maintain weight loss through lifestyle changes.
What does NHS NICE say about stopping Mounjaro?
NICE guidance does not specify a fixed duration for Mounjaro treatment. NICE recommends ongoing clinical review at least every 12 weeks to assess weight loss, tolerability, and health benefits. If weight loss plateaus, side effects are unmanageable, or health goals are achieved, discontinuation should be considered in discussion with the patient and clinical team.
Will I regain weight if I stop Mounjaro?
Weight regain is likely if dietary and activity habits return to pre-treatment levels. Clinical trials show most weight returns within months of stopping. However, if you have made lasting lifestyle changes — using tools like our free progress tracker and sustained physical activity — you may maintain significant loss. Your prescriber or dietitian can help you plan for this transition.
How do I stop Mounjaro safely on the NHS?
Contact your tier 3 weight management service or GP to discuss stopping. They will review your progress, discuss maintenance strategies, and ensure you have access to ongoing behavioural support. Unlike some medications, Mounjaro does not require gradual dose reduction. Your team may recommend regular follow-ups to monitor your weight and health over the following months.
What's the difference between stopping Mounjaro and Wegovy?
Both are GLP-1-type medications (Mounjaro is dual GIP/GLP-1), so the stopping process is similar — no tapering required, appetite returns gradually, and weight regain risk is comparable. The main difference is access: Mounjaro on the NHS goes through tier 3 specialist services, whereas Wegovy eligibility and stopping decisions follow the same NHS pathway. Your prescriber will tailor the approach to your individual circumstances.
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.