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 Dosage Chart: UK Costs and How to Access
Mounjaro (tirzepatide) is available in the UK as a prescription-only weight management injection, with doses ranging from 2.5 mg to 15 mg given once weekly. Understanding the dosage progression, costs, and how to access this medication is essential if you're considering prescription weight loss support. This guide covers the standard dose titration schedule used in UK clinical practice, UK private prescription costs, and how the NHS vs private routes differ—helping you make an informed decision about your options.
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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 Dosage Schedule and Private Prescription Costs in the UK
Mounjaro follows a step-wise dose titration schedule:
- 2.5 mg weekly — weeks 1–4 (starting dose)
- 5 mg weekly — weeks 5–8
- 7.5 mg weekly — weeks 9–12
- 10 mg weekly — weeks 13–16
- 12.5 mg weekly — weeks 17–20
- 15 mg weekly — week 21 onwards (maximum dose)
Each dose is delivered via the Mounjaro KwikPen, a pre-filled device containing four weekly injections. Most people remain on 5 mg or 10 mg as their maintenance dose; not everyone requires the maximum 15 mg dose.
UK private prescription costs typically range from £150–£280 per month depending on dose and provider, though prices vary. Unlike NHS prescriptions, private costs are not capped, so shopping around for reputable GPhC-registered providers is important. Always verify that any provider conducts a proper clinical assessment before issuing a prescription.
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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.
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NHS Access vs Private Prescription Routes
NHS access is through specialist tier 3 or tier 4 weight management services, typically requiring a GP referral. Availability varies significantly by region, and waiting lists can extend to several months or longer. Once approved, Mounjaro is dispensed free on the NHS, but access criteria are strict and not all regions fund it equally.
Private access is faster—you can access prescription weight loss medication without an NHS referral by completing an online clinical assessment with a UK-licensed prescriber. If clinically appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy. This route offers flexibility and no waiting list, but costs are borne entirely by you. Both routes require a proper medical assessment; neither offers medication without clinical evaluation.
- 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 is the starting dose of Mounjaro in the UK?
The starting dose is 2.5 mg once weekly for the first 4 weeks. This allows your body to adjust to the medication before dose increases. Increasing too quickly can increase side effects like nausea.
How long does it take to reach the maximum Mounjaro dose?
It typically takes 20–24 weeks to reach the maximum 15 mg dose if you increase every 4 weeks. However, most people achieve effective weight loss at 5 mg or 10 mg and don't progress to 15 mg.
How much does Mounjaro cost privately in the UK per month?
Private prescription costs typically range from £150–£280 per month, depending on the dose and prescribing provider. Costs vary, so it's worth comparing GPhC-registered pharmacies, though the price difference is usually modest.
Can I get Mounjaro on the NHS in the UK?
Yes, but only through specialist weight management services (tier 3 or 4). You'll need a GP referral, and availability varies significantly by region. Waiting lists are often lengthy, and eligibility criteria are strict.
What's the difference between Mounjaro and Wegovy dosing?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist with a maximum dose of 15 mg weekly, while Wegovy (semaglutide) is a GLP-1-only agent with a maximum of 2.4 mg weekly. Both are once-weekly injections, but Mounjaro's dual mechanism may explain different individual responses.
Ready to take control of your weight loss journey?
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