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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Can You Stay On Mounjaro Forever — Long-Term Use Explained
Whether you can stay on Mounjaro (tirzepatide) long-term depends on your individual health, weight loss goals, and how well you tolerate the medication. Most people use Mounjaro as part of a structured weight management programme rather than indefinitely. This guide explains long-term use, NHS and private access routes in the UK, what ongoing treatment costs, and what to expect if you decide to continue or stop the medication.
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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 Can You Stay On Mounjaro — NHS and Private Guidance
There is no fixed time limit for how long you can take Mounjaro in the UK — it depends on your individual circumstances, how well it works for you, and whether your prescriber considers it safe to continue.
Current UK guidance:
- Mounjaro is typically used as part of a structured weight management programme alongside diet and physical activity
- Most people use it for 1–3 years, though some continue longer if they remain eligible and tolerant
- Your prescriber will regularly review whether to continue, adjust dose, or pause treatment
- If you stop Mounjaro, weight can gradually return, especially without sustained lifestyle changes
- The Mounjaro KwikPen device requires weekly injections at a dose between 2.5 mg and 15 mg, with at least 4 weeks at each dose level before escalation
Long-term use is generally considered safe in clinical practice, but it requires ongoing medical supervision, regular health checks, and reassessment of whether the benefits continue to outweigh any side effects.
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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.
Mounjaro Cost in the UK — NHS vs Private Routes
NHS access: Mounjaro is funded through NHS specialist weight management services in some regions, though availability varies significantly by integrated care board (ICB). Referral from your GP to a tier 3 or tier 4 specialist service is typically required, and waiting lists can be several months to over a year in many areas.
Private prescription costs: Through private online prescribing services, Mounjaro costs between approximately £129–£280 per month depending on dose, with higher doses (10–15 mg) at the upper end. You will need an online clinical assessment with a UK-licensed prescriber before a private prescription is issued. Costs cover the medication and prescription only — not GP consultations or specialist monitoring.
Whether NHS or private access is suitable depends on your eligibility, local availability, and preference for clinical oversight during long-term treatment.
- 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.
Do I have to stay on Mounjaro forever to keep weight off?
No. Mounjaro is a tool to support weight loss alongside diet and exercise, not a lifetime requirement. However, research shows that weight often returns if you stop the medication without maintaining the lifestyle changes you made while taking it. Your prescriber will help you decide when to stop based on your weight loss goals and health improvements.
What happens if I stop taking Mounjaro?
Weight loss tends to plateau and may gradually return over months, particularly if dietary habits revert. Appetite may increase as the medication effects wear off (usually within 2–4 weeks of stopping). This is why sustainable lifestyle change during Mounjaro use is important. Your prescriber can advise on the best time to stop and how to transition safely.
Is Mounjaro covered by the NHS long-term in the UK?
Mounjaro is available through NHS specialist weight management services in many regions following NICE approval, but availability and funding duration vary by area. Some ICBs offer it for 1–2 years, others for shorter periods. Contact your GP about referral to specialist services to check local availability and typical treatment duration in your area.
How much does private Mounjaro cost per month in the UK?
Private Mounjaro costs approximately £129–£280 per month depending on dose. Higher maintenance doses (15 mg) cost more than lower starter doses (2.5–5 mg). Prices vary slightly between private prescribing services. Costs include the medication and prescription but not separate GP or specialist consultations, which may be charged separately by some providers.
Can I use our GLP-1 weight loss calculator to estimate long-term results?
Yes — our free GLP-1 weight loss calculator can help you project potential weight loss at different doses of Mounjaro over time. Use it alongside your BMI calculator and progress tracker to monitor your actual results if you decide to start treatment. This helps you set realistic expectations for long-term use.
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.