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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Mounjaro Milligrams: UK Dosing, Access & Costs Explained
Mounjaro (tirzepatide) is available in five different milligram doses in the UK, starting at 2.5 mg and increasing to a maximum of 15 mg. This guide explains the dosing schedule, how prescribers adjust your dose, what you can expect at each milligram level, and the different routes to access Mounjaro in the UK—whether through the NHS or private prescription. Understanding the dose progression and associated costs can help you make informed decisions about whether this medication is right for you.
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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.
Mounjaro Doses in the UK: The Complete Titration Schedule
Mounjaro is dispensed in a pre-filled KwikPen device, and each pen contains 4 weekly injections. The standard titration schedule increases your dose every 4 weeks:
- Weeks 1–4: 2.5 mg once weekly (starting dose)
- Weeks 5–8: 5 mg once weekly
- Weeks 9–12: 7.5 mg once weekly
- Weeks 13–16: 10 mg once weekly
- Weeks 17–20: 12.5 mg once weekly
- Weeks 21+: 15 mg once weekly (maximum dose)
Your prescriber may adjust this timeline based on how you respond. Clinical trials showed that adults on the 15 mg dose lost an average of around 21% of their body weight over 72 weeks—though individual results vary significantly. Not everyone needs the maximum dose; some people reach their weight loss goals at lower milligrams. Your prescriber will assess what dose is right for you.
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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
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How to Access Mounjaro in the UK: NHS vs Private Routes
NHS access: Mounjaro is available through NHS tier 3 specialist weight management services following NICE approval. You'll need a GP referral and may face lengthy waiting lists depending on your region. Private access: You can obtain Mounjaro through a GPhC-registered online pharmacy following a consultation with a UK-licensed prescriber—no NHS referral required. Private costs typically range from £129 to £320 per month depending on the dose, with higher milligrams (10–15 mg) costing more than lower starting doses. An online clinical assessment will determine your eligibility based on your BMI, health conditions, and medication history. Both routes require a valid prescription; Mounjaro cannot be purchased without one.
- 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.
What's the difference between Mounjaro doses—will a higher milligram always work better?
Not necessarily. Higher doses may produce greater average weight loss in clinical trials, but individual response varies. Some people achieve excellent results at 5 mg or 7.5 mg, whilst others need to reach 15 mg. Your prescriber will start you low and increase gradually, monitoring your progress and side effects. The goal is finding the dose that works best for your body.
How much does Mounjaro cost privately in the UK per month?
Private prescription costs range from approximately £129 (starting doses like 2.5–5 mg) to £320+ per month (maximum 15 mg dose). Prices vary slightly between pharmacies. Most offer subscription options where you receive your pre-filled pen monthly. An online consultation typically costs £20–£50 in addition to the medication cost.
Can I get Mounjaro on the NHS in the UK?
Yes, but access is through specialist tier 3 weight management services, not standard GP prescription. You need a GP referral and meet NICE eligibility criteria (BMI ≥30, or BMI ≥27 with weight-related health conditions). Waiting times vary significantly by region—some areas have waiting lists of several months to years.
What happens if I skip a Mounjaro dose or miss an injection?
If you miss your injection, take it within 4 days of the scheduled date and continue your normal weekly schedule. If more than 4 days have passed, skip that dose and resume your next scheduled injection. Never take a double dose. Always maintain at least 72 hours between injections.
Is Mounjaro the same as tirzepatide, and why are there two names?
Yes—Mounjaro is the brand name for tirzepatide. It's a dual GIP and GLP-1 receptor agonist, which is different from single-action GLP-1 medications like Wegovy (semaglutide). In clinical trials, tirzepatide produced slightly higher average weight loss than semaglutide, though results vary individually. Your prescriber will discuss which medication suits you best.
Ready to take control of your weight loss journey?
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