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 Long Do People Stay On Mounjaro in the UK?
Most people taking Mounjaro (tirzepatide) stay on the medication for 6 months to several years, depending on their weight loss goals, response to treatment, and whether they continue to benefit from it. There's no fixed duration — treatment continues as long as it's helping with weight management and your prescriber agrees it's suitable for you. In the UK, access to Mounjaro is available through NHS specialist weight management services or private prescription following an online clinical assessment. Understanding the typical treatment timeline and costs can help you plan your weight management journey.
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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.
Treatment Duration and Costs in the UK
How long someone stays on Mounjaro depends on several factors: their individual weight loss response, whether they're reaching their health goals, side effect tolerance, and whether their prescriber recommends continuing. Most people continue for at least 6 months to 1 year to see meaningful results, as the dose titration process takes 4–5 months to reach the maximum 15 mg dose. Some people stop after achieving their target weight, others continue long-term for weight maintenance. If you stop Mounjaro, weight can return — this is why many people stay on it indefinitely.
UK private prescription costs vary by provider and dose. Starter doses (2.5–5 mg) typically cost £129–£180 per month, while higher maintenance doses (10–15 mg) range from £200–£320 per month. A full KwikPen (4 weeks) is the standard dispensing unit. These are approximate ranges — always check your chosen provider's current pricing. Unlike some medications, Mounjaro is not routinely available on the NHS outside specialist tier 3/4 weight management services.
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.
NHS vs Private Access in the UK
NHS access: Mounjaro is available through NHS specialist weight management services following NICE approval, but availability is patchy across regions. Your GP can refer you to your local tier 3 or tier 4 weight management service if you meet eligibility criteria (BMI ≥30, or ≥27 with comorbidities). NHS waiting lists can be very long — many areas have 12–24 month waits.
Private access: Available much faster through GPhC-registered online pharmacies. You complete an online consultation with a UK-licensed prescriber, who assesses your eligibility and issues a prescription if appropriate. This route bypasses NHS waiting lists and gives you control over your treatment timeline. Prescription fees vary by provider (typically £20–£50 per consultation).
- 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?
Yes — you can stop at any time, but discuss this with your prescriber first. If you stop, your appetite typically returns to baseline within weeks, and weight loss may reverse over time. Many people stay on Mounjaro long-term for weight maintenance rather than stopping completely.
Is Mounjaro covered by the NHS in the UK?
Mounjaro is available through NHS specialist weight management services for eligible adults, but regional availability is very limited. Most people access it privately. Check with your GP about local NHS tier 3 services, but expect long waiting lists in most areas.
How much does a Mounjaro KwikPen cost privately?
A single KwikPen (4 weeks of doses) costs approximately £129–£320 depending on the dose strength and your provider. Starter doses are cheaper; higher maintenance doses (10–15 mg) cost more. Check your chosen pharmacy's current pricing.
How do I get a private Mounjaro prescription in the UK?
Use a GPhC-registered online pharmacy. Complete an online health questionnaire, have a consultation with a UK-licensed prescriber, and receive your prescription if eligible. The process typically takes 24–48 hours from consultation to dispensing.
What happens if I stay on Mounjaro for years?
Long-term safety data is still emerging, but clinical experience suggests many people continue successfully for extended periods. Regular check-ins with your prescriber are important. Use our GLP-1 weight loss calculator to track projected outcomes and monitor progress over time.
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.