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 Come Off Mounjaro?
Deciding when to stop Mounjaro (tirzepatide) is a decision that should always be made with your prescriber, not independently. There is no fixed timeframe for how long you should take Mounjaro, and stopping the medication requires careful medical guidance. This guide explains the UK context for discontinuing Mounjaro, what NHS guidance says, and what you should expect if you decide to come off treatment with your GP or specialist.
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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.
Stopping Mounjaro — NHS and Medical Guidance
There is no set duration for Mounjaro treatment in the UK. You may continue taking it for as long as it remains effective and you tolerate it well — which could be months, years, or longer. However, stopping should only be considered following a discussion with your prescriber.
- Your GP or specialist will advise on stopping — never discontinue without medical guidance
- Common reasons to stop include: achieving your weight loss goal, experiencing intolerable side effects, changes in health status, or pregnancy planning
- NICE guidance emphasises that weight loss medications work best when combined with lifestyle changes, and long-term use may be necessary to maintain results
- If you stop Mounjaro, weight regain is common — studies show that people often regain weight when treatment ends unless diet and exercise habits are firmly established
- Your prescriber may recommend a gradual dose reduction rather than stopping abruptly, though this varies by individual
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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 discontinue Mounjaro, appetite regulation typically returns to baseline within days to weeks. Weight regain can occur relatively quickly if lifestyle changes (diet and physical activity) are not maintained. Many people find that the habits developed while on treatment — such as smaller meal portions and regular movement — help prevent rapid weight return, but this requires ongoing commitment.
Before stopping, discuss with your prescriber whether stepping down to a lower dose first might help, or whether maintaining your current dose longer would be beneficial. Your healthcare team can assess your individual circumstances, including your weight loss progress, side effects, and long-term health goals, to recommend the safest approach for you personally.
If you're considering stopping Mounjaro, use our free GLP-1 weight loss calculator to review what your weight loss journey has been, and track future progress with our progress tracker. Having clear data on your results can help you and your prescriber make an informed decision about continuing or discontinuing treatment. Your GP or specialist can also refer you to a tier 3 weight management service for additional support with lifestyle maintenance if needed.
- 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?
No. You should never stop Mounjaro without consulting your GP or prescriber first. Stopping suddenly or independently can affect your health and weight management plan. Always discuss your reasons for wanting to stop — your healthcare team may suggest adjustments, a gradual dose reduction, or additional support instead.
What happens to weight when you stop taking Mounjaro?
Weight regain is common after stopping Mounjaro, as appetite regulation returns to normal. How much weight you regain depends on whether you maintain the dietary and lifestyle changes you developed while on treatment. Some people regain weight within weeks; others maintain results if they continue healthy habits.
Does NICE say how long you should take Mounjaro?
NICE does not specify a fixed duration. Guidance emphasises that weight loss medications should be continued as long as they remain effective and tolerated, with regular review by your healthcare team. Individual circumstances, weight loss goals, and health status determine the right timeframe for you.
What if I want to come off Mounjaro because of side effects?
If you're experiencing troublesome side effects, speak to your GP or prescriber before stopping. They may recommend a dose reduction rather than stopping completely, adjusting timing of doses, or waiting as your body adapts. Many side effects improve over time, but your prescriber can help find the best solution.
Will my appetite return if I stop Mounjaro?
Yes. Your appetite and hunger signals typically return to your baseline within days to weeks of stopping. This is why maintaining the portion control habits and exercise routines you developed during treatment is important for preventing rapid weight regain.
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.