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 Often Do You Take A Mounjaro Maintenance Dose?
Mounjaro maintenance doses are taken once every seven days as a single injection. After you reach your target maintenance dose (typically 10mg, 12.5mg, or 15mg), you continue with one weekly injection for as long as the medication remains effective and suitable for you. The specific maintenance dose is determined during your dose titration period and adjusted by your prescriber based on your individual response and tolerance.
10,000+ calculations today ยท NHS-aligned thresholds ยท 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/mยฒ).
While BMI isn't a perfect measure โ it doesn't account for muscle mass, bone density, or fat distribution โ 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 โ 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.
Mounjaro Maintenance Schedule And UK Prescription Access
Once you reach your target maintenance dose, Mounjaro follows a consistent once-weekly injection schedule. Most patients stabilise on either 10mg, 12.5mg, or 15mg per week, though some may maintain on lower doses if they experience good results with fewer side effects. Each dose is administered using a pre-filled KwikPen device, with each pen containing four weekly doses (one month's supply). In the UK, you can access Mounjaro through either the NHS via specialist tier 3 weight management services, or privately through GPhC-registered online prescribing services. Private prescription costs typically range from ยฃ129 to ยฃ320 per month depending on your maintenance dose โ lower doses cost less than higher doses. NHS access is free at the point of use but involves referral to specialist services and can involve significant waiting times in many regions.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care โ 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 โ 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 โ completely free.
Understanding Mounjaro Cost, Eligibility, And The Prescription Process
To access Mounjaro in the UK, you'll need a prescription from a licensed prescriber following a clinical assessment. Your GP can refer you to NHS specialist weight management services, or you can use a private online consultation service where a UK-licensed prescriber reviews your medical history, current medications, and eligibility criteria before issuing a prescription if appropriate. Eligibility typically includes a BMI of 30 or above, or 27โ29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. Once prescribed, you'll receive your Mounjaro pens by post and can self-inject at home once weekly on your chosen day. Your progress should be monitored regularly โ via your prescriber if private, or your NHS specialist team.
- 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 โ 5mg โ 7.5mg โ 10mg โ 12.5mg โ 15mg
- GLP-1 receptor agonist
- Up to 15โ17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg โ 0.5mg โ 1mg โ 1.7mg โ 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 | 15โ22.5% | 12โ17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20โ32 weeks | 16โ20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | ยฃ150โยฃ250/month | ยฃ150โยฃ300/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 โ 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 often exactly do you inject Mounjaro once you're on maintenance?
Once every seven days. You choose your injection day and stick to the same day each week. You can take your dose within a 24-hour window if needed โ so if you normally inject on Monday, you could do it anytime between Sunday and Tuesday if your schedule changes one week.
What happens if I miss a Mounjaro maintenance dose?
If you miss a dose within 4 days, take it as soon as you remember and continue your normal schedule the following week. If more than 4 days have passed, skip that dose and take your next dose on your normally scheduled day. Never take two doses within 3 days to make up for a missed injection.
How much does Mounjaro cost privately in the UK on maintenance?
Private Mounjaro costs typically range from ยฃ129 to ยฃ320 per month depending on your maintenance dose. Lower maintenance doses (10mg) are generally cheaper than higher doses (15mg). Prices vary slightly between different private prescribing services, so it's worth comparing costs before starting treatment.
Can I get Mounjaro on the NHS for ongoing maintenance?
Yes, Mounjaro is available through NHS specialist tier 3 weight management services following NICE approval. Access is free at the point of use, but you'll need referral from your GP and assessment by a specialist service. Availability and waiting times vary significantly by region โ contact your local ICB for information about services in your area.
How do I know if I'm on the right maintenance dose?
Your prescriber will assess your response after 4 weeks on each dose. The right maintenance dose should provide effective weight loss while keeping side effects manageable. If you're losing weight steadily and tolerating the injections well, you're likely on an appropriate dose. If side effects are severe, your prescriber may adjust down; if weight loss plateaus, they may suggest increasing.
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.