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 Maintain Weight On Mounjaro
Maintaining weight loss after reaching your goal on Mounjaro requires a strategic approach combining continued medication use, lifestyle habits, and GP oversight. Many people using this weekly weight loss injection worry about regaining weight once they stop, but evidence suggests that staying on a stable maintenance dose—alongside consistent dietary and activity changes—can help preserve results. This guide covers NHS-aligned maintenance strategies for UK adults using tirzepatide.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
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.
Maintenance Strategies While Taking Mounjaro
Weight maintenance on Mounjaro typically involves staying on a stable dose rather than stopping immediately. Most people find that stopping the injection entirely can lead to appetite return and gradual weight regain within weeks. Your prescriber may recommend:
- Continuing at your effective dose: If 10 mg or 15 mg worked well, maintaining that dose helps appetite remain suppressed and food intake stays lower.
- Dose reduction to a lower maintenance level: Some patients step down to 5 mg once-weekly if 10 mg or 15 mg causes ongoing side effects, though appetite may increase slightly.
- Regular GP check-ins: NHS specialist services typically review weight and progress every 3–6 months to adjust your dose if needed.
- Consistent calorie awareness: Continue using MyWeightCheck's free BMI calculator and progress tracker to monitor changes. Even on Mounjaro, you must maintain a stable or slight deficit to prevent regain.
The KwikPen device makes weekly dosing straightforward, supporting adherence to your maintenance plan.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Lifestyle Factors That Support Long-Term Weight Maintenance
Medication alone does not assures permanent weight maintenance—you must also sustain the behaviours that created your initial loss. Nutrition and movement matter just as much on maintenance as during active weight loss. Focus on protein intake (1.2–1.6g per kg body weight) to preserve muscle, include regular activity (150 minutes moderate cardio weekly per NHS guidance), and practise mindful eating to avoid portion creep. Use our free GLP-1 weight loss calculator to understand how your maintenance strategy differs from your active-loss phase. Many people successfully maintain by adopting a Mediterranean-style diet pattern, reducing ultra-processed foods, and building sustainable routines rather than temporary restrictions.
- 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.
How long should I stay on Mounjaro once I reach my goal weight?
There is no fixed timeline. Many people continue long-term if weight stays stable and side effects are manageable. Your GP or specialist will advise based on your individual health and weight patterns. Stopping abruptly often leads to regain within weeks, so most people either maintain their dose or step down gradually.
Can I stop Mounjaro and keep the weight off?
Some people maintain weight after stopping, but most experience appetite return and gradual regain within 6–12 months. Evidence suggests that staying on a stable maintenance dose significantly improves long-term results. Your prescriber can discuss whether continuation, reduction, or stopping is right for you.
What should my maintenance calorie intake be on Mounjaro?
This varies by individual, but generally your maintenance intake is your current weight multiplied by 22–25 (rough estimate). For example, an 80kg person might maintain around 1,760–2,000 kcal/day. Mounjaro suppresses appetite, so you'll naturally eat less. Track intake for 1–2 weeks to find your balance, and adjust if weight creeps up or down.
How often will my GP review my Mounjaro dose during maintenance?
NHS specialist services typically offer reviews every 3–6 months, though frequency varies by your ICB (Integrated Care Board). Private prescribers generally offer monthly or 3-monthly check-ins. Discuss your review schedule with your healthcare provider.
Should I stay on Mounjaro permanently?
There is no formal guidance on permanent use. Mounjaro is approved for ongoing weight management, and some people use it long-term successfully. Others step down after 2–3 years. This decision should be made with your GP or specialist based on your weight stability, health improvements, side effects, and personal preference.
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.