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 Do You Stop Taking Mounjaro?
There is no set "stopping point" for Mounjaro — whether you continue depends on your individual health goals, how well it's working, and your prescriber's guidance. Unlike a course of antibiotics, Mounjaro is typically a longer-term weight management treatment. Your GP or prescriber will review your progress regularly to decide if continuing is right for you. Understanding how long you might take it, and what happens when you stop, can help you plan your weight management journey effectively.
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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 Long Do People Typically Stay on Mounjaro?
Mounjaro is not a short-term course of medication — it's designed as ongoing support for weight management. Clinical trials followed participants for up to 72 weeks, but many people in the UK stay on Mounjaro for much longer if it's helping and their GP believes it remains appropriate. The duration varies widely: some people use it for 6–12 months to reach a target weight, whilst others continue for years as part of their long-term health strategy.
Your prescriber will typically:
- Review your progress every 3–6 months
- Check how well the tirzepatide is working for you
- Monitor your side effects and how you're tolerating the injections
- Assess whether your BMI, weight, and weight-related health conditions are improving
- Discuss whether to continue, adjust the dose, or consider stopping
There's no NHS NICE guidance stating an exact maximum duration — the decision is individualised based on your response and ongoing need.
Clinically BackedWeight Loss
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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 Taking Mounjaro?
When you stop Mounjaro, the medication leaves your system relatively quickly — tirzepatide has a half-life of about 5 days, meaning roughly half is cleared from your body each week. Within 2–3 weeks, most of the drug is gone, and your appetite-regulating hormones gradually return to baseline.
After stopping, expect:
- Appetite and food cravings to gradually return to pre-Mounjaro levels
- Possible weight regain if lifestyle changes aren't maintained
- Gastrointestinal side effects to resolve within a few weeks
- A need to focus on sustainable diet and physical activity to prevent weight rebound
Research shows that weight often returns after stopping GLP-1 medication if diet and exercise habits haven't changed, which is why your prescriber may discuss long-term strategies with you.
- 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 you stop Mounjaro whenever you want?
You can stop taking Mounjaro at any time — it's prescription-only, so you control your decision with your prescriber's guidance. However, it's best to discuss stopping with your GP or the clinic managing your treatment, rather than stopping abruptly. They can help you plan for potential weight regain and discuss maintenance strategies.
Will I regain weight after stopping Mounjaro?
Weight regain is common after stopping — clinical data shows that appetite and hunger hormones return to baseline, often leading to weight increase if diet and activity levels don't remain changed. Using our free progress tracker can help you monitor your weight during the transition off the medication.
How does Mounjaro compare to Wegovy for duration of treatment?
Both Mounjaro and Wegovy are longer-term treatments without a fixed stopping point. The mounjaro vs wegovy comparison shows similar patterns: both may be used for months or years depending on individual response. Your prescriber decides the best option and duration for you.
What if I want to stop Mounjaro due to side effects?
If you're experiencing troublesome side effects, contact your prescriber — don't stop suddenly. They may reduce your dose, pause treatment briefly, or discuss alternatives. Many side effects (nausea, constipation) improve after the first few weeks as your body adjusts.
Is there guidance on stopping Mounjaro from NHS NICE?
Mounjaro NHS NICE guidance approves it for weight management in eligible adults, but doesn't specify a fixed stopping duration. The decision to continue or stop is made between you and your prescriber based on your individual health goals, weight loss progress, and ongoing benefit versus side effects.
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.