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
How to Keep the Weight Off After Mounjaro
Stopping Mounjaro after successful weight loss can be challenging — many people regain weight once they stop the weekly weight loss injection. The good news is that the habits you build whilst on Mounjaro can help you maintain your results long-term. This guide covers practical strategies to keep weight off after treatment ends, when to involve your GP, and what to expect during the transition period. Managing your weight sustainably after a prescription weight loss medication requires planning, support, and realistic expectations.
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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.
Building Sustainable Habits During Mounjaro Treatment
The most effective approach to maintaining weight loss after Mounjaro is to focus on behaviour change whilst you're still taking the medication. Mounjaro works by reducing appetite and food cravings, which creates a window of opportunity to develop healthier eating patterns and routines.
- Track your food intake: Use our free progress tracker or a food diary to monitor what you eat. This builds awareness and helps identify patterns you want to keep after stopping.
- Develop sustainable meal patterns: Rather than restrictive dieting, focus on finding balanced meals you genuinely enjoy — whole grains, lean proteins, vegetables, and healthy fats in proportions that satisfy you.
- Increase physical activity gradually: Combine dietary changes with regular movement. This protects muscle mass during weight loss and makes long-term weight management easier.
- Address emotional eating: If you use food for comfort, identify alternative coping strategies now — this is crucial for maintaining results after stopping.
The habits you establish now are the foundation of your long-term success. Mounjaro acts as a teaching tool; the real work is integrating these behaviours into your daily life.
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 Mounjaro
When you stop taking Mounjaro, appetite hormones gradually return to pre-treatment levels over several weeks. This means hunger and food cravings will gradually increase — this is normal and expected.
- Weight regain risk: Studies show that without sustained lifestyle changes, people typically regain 50–75% of lost weight within 1–2 years of stopping a GLP-1 medication like semaglutide.
- Gradual transition: Your GP may gradually reduce your dose before stopping completely, rather than stopping abruptly.
- Ongoing support: Speak to your GP or a registered dietitian about your transition plan. Continued monitoring helps catch weight regain early.
The transition is manageable if you've built strong habits during treatment. This is why starting behaviour change immediately — not at the end of treatment — makes such a significant difference to long-term results.
- 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 definitely regain weight when I stop Mounjaro?
Weight regain is common but not inevitable. People who maintain the dietary and lifestyle changes they made during treatment are far more likely to keep weight off long-term. The habits matter more than the medication. Your GP can help you plan a sustainable approach for after you stop.
Can I restart Mounjaro if I regain weight after stopping?
This depends on your individual circumstances and NHS or private prescriber guidance. Some people use periodic courses of treatment alongside ongoing lifestyle management. Discuss your options with your GP or prescriber — they can assess what's appropriate for your situation.
How much physical activity do I need to maintain weight loss?
The NHS recommends at least 150 minutes of moderate-intensity activity per week (or 75 minutes vigorous) plus strength training twice weekly. However, any regular movement helps. Find activities you enjoy — walking, cycling, swimming — and aim for consistency rather than intensity.
Should I see a dietitian after stopping Mounjaro?
Yes, if possible. A registered dietitian can help you plan balanced meals, navigate cravings, and adjust portions as your appetite returns. Many NHS services offer dietitian support through specialist weight management clinics. Speak to your GP about a referral.
What's the difference between Mounjaro and Wegovy for weight management?
Both are prescription-only injections, but they work slightly differently. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro's dose range (2.5–15mg weekly) is different from Wegovy (0.25–2.4mg weekly). Your prescriber decides which is most appropriate for you.
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.