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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How to Change Your Mounjaro Supplier in the UK
If you're currently taking Mounjaro (tirzepatide) and want to switch suppliers — whether for cost, convenience, or access reasons — you have several options in the UK. This guide explains how to change your Mounjaro provider, what costs you should expect, and the differences between NHS and private prescription routes. Whether you're moving from NHS specialist services to private prescription, or switching between private providers, understanding the process helps you access this weight management injection safely and affordably.
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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.
UK Mounjaro Costs and Private Prescription Access
Private Mounjaro costs in the UK vary by dose and provider, typically ranging from £100–£350 per month depending on your current dose level. Lower doses (2.5–5 mg) tend to cost less, while maintenance doses (10–15 mg) cost more. Private providers offer convenient online consultations with UK-licensed prescribers, meaning you don't need an NHS referral to tier 3 specialist services. The Mounjaro KwikPen contains 4 weekly doses, so monthly costs usually represent a 4-week supply. Costs may be higher in your first month if you're starting from a lower dose and titrating upwards — remember that each dose level typically requires 4 weeks before escalation.
- Starting doses (2.5–5 mg): approximately £100–£150 per month
- Mid-range doses (7.5–10 mg): approximately £180–£250 per month
- Maximum dose (15 mg): approximately £280–£350 per month
Some private providers offer subscription discounts or bulk purchase options — it's worth comparing offers across GPhC-registered pharmacies. Unlike NHS services, private prescription costs are not capped and vary by provider, so shopping around can make a genuine difference to your budget.
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.
Switching Suppliers: NHS to Private, or Private to Private
If you're currently receiving Mounjaro through NHS tier 3 specialist services and want to switch to private prescription, you'll need a new prescription from a private UK-licensed prescriber. This requires a fresh online consultation — your NHS prescription cannot be transferred directly. The private prescriber will assess your eligibility and current dose level before issuing a prescription to a GPhC-registered pharmacy. If you're already on private prescription and want to change supplier, simply book a consultation with a different prescriber — there's no requirement to notify your previous provider. When switching, allow at least 2–3 days for your new prescription to be dispensed, so plan ahead to avoid running out of doses. Always store your Mounjaro KwikPens correctly (refrigerated at 2–8°C if unopened) and check expiry dates before switching to a new supplier.
- 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.
Why would I change my Mounjaro supplier?
Common reasons include seeking lower costs, faster access than NHS waiting lists, switching from NHS tier 3 services to private prescription for convenience, or simply comparing different private provider pricing. Some people also change suppliers to access additional support services or different dose availability.
Is it safe to switch Mounjaro suppliers?
Yes, switching is safe as long as you maintain consistent dosing and don't miss or double up on injections. If switching between suppliers, plan the changeover to avoid running out of doses. Always ensure your new supplier provides the same dose level you're currently on — your prescriber will confirm this during consultation.
What's the difference between NHS and private Mounjaro cost?
NHS tirzepatide is free through tier 3 specialist services, but access involves referral, assessment, and often long waiting lists. Private prescription requires paying per month but offers faster access and no waiting list — you can start consultation within days. NHS access is based on eligibility; private access requires a valid prescription from a UK-licensed prescriber.
Can I use my NHS Mounjaro prescription with a private pharmacy?
Yes — if your NHS tier 3 service issues a prescription, any GPhC-registered pharmacy can dispense it. However, private pharmacies may charge a dispensing fee on top of the NHS medication cost. Always clarify any additional costs before giving consent.
How long does it take to switch suppliers?
Online private consultations typically take 24–48 hours from booking to prescription issue. Pharmacy dispensing usually takes 1–3 working days depending on stock and delivery method. Plan the switch carefully to ensure at least 5–7 days before your next scheduled injection to avoid gaps in treatment.
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.