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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Is Mounjaro a Maintenance Dose For Life?
Mounjaro (tirzepatide) is not typically considered a lifelong maintenance treatment in the way insulin is for type 1 diabetes. Instead, it's usually prescribed as a time-limited weight management tool to help you reach a healthier weight alongside diet and exercise changes. Once you reach your target weight, your prescriber may discuss discontinuing the medication or adjusting your approach. However, some people may benefit from longer-term or intermittent use depending on their individual circumstances and how their weight responds when treatment stops.
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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.
How Long Do People Typically Stay On Mounjaro?
Clinical evidence and UK prescribing guidance suggest Mounjaro is intended as a medium to long-term weight management tool, not necessarily forever. Most people follow a structured treatment plan: starting at 2.5 mg and titrating up to an effective maintenance dose (typically 5–15 mg once weekly) over several months. Once stable at a dose that supports weight loss without intolerable side effects, you may stay on that dose for 1–3 years or longer, depending on your progress and goals.
However, the duration isn't predetermined. Your GP or prescriber will regularly review whether you're benefiting from continuing treatment. If you've reached a sustainable weight and can maintain it through lifestyle changes alone, stopping may be discussed. Equally, if you regain weight after stopping, restarting Mounjaro may be an option.
Using our GLP-1 weight loss calculator, you can estimate potential outcomes at your current dose to help inform these conversations with your prescriber.
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.
What Happens If You Stop Taking Mounjaro?
Weight regain is common after stopping Mounjaro. Clinical data suggests many people return towards their pre-treatment weight within months if lifestyle changes alone are not maintained. This doesn't mean the medication "failed"—it reflects how the body naturally regulates appetite and metabolism.
Some people experience a rebound in hunger and food cravings within weeks of stopping, whilst others find their appetite remains more controlled. Gradual weight gain over 6–12 months is typical rather than sudden loss of all progress. Your prescriber may recommend:
- Continuing at a lower maintenance dose if weight is stable
- Restarting if significant regain occurs and you meet eligibility criteria
- Using breaks between treatment cycles (though evidence for this approach is limited)
- Intensifying diet and exercise support when stopping
- 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 stay on Mounjaro indefinitely?
There's no absolute contraindication to long-term use, but Mounjaro isn't licensed as a "for life" medication in the UK. Your prescriber will periodically review whether you're still benefiting and tolerating it well. Some people may stay on a maintenance dose for many years, whilst others may stop and restart. The decision is individualised.
What's the typical maintenance dose for ongoing treatment?
Most people maintain effectiveness at 5–15 mg once weekly. The dose varies by individual response and tolerance. Some stay stable at 5–10 mg, whilst others require 15 mg (the maximum). Your prescriber will find the lowest effective dose for you to minimise side effects whilst supporting weight management.
Is Mounjaro a UK NHS prescription or private only?
Mounjaro is available via NHS specialist tier 3 weight management services in some areas, though access is variable and waiting lists can be long. It's also available privately through UK-licensed prescribers following an online clinical assessment. Either route requires a prescription—it's not available over-the-counter.
How does Mounjaro compare to Wegovy for long-term use?
Both are prescription-only GLP-1 medications licensed for weight management. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with slightly higher average weight loss in trials. Wegovy (semaglutide) is a GLP-1 agonist only. Long-term use patterns are similar for both—neither is formally licensed as permanent therapy, and decisions to continue or stop are made with your prescriber based on individual progress.
What should I do to prepare for stopping Mounjaro?
Work with your prescriber several weeks in advance. Intensify diet, exercise, and behaviour change strategies before stopping. Consider whether ongoing support—such as a dietitian or structured weight management programme—would help maintain progress. Track your weight using our free progress tracker to monitor any changes and discuss results with your prescriber promptly.
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.