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
When Did Mounjaro Come Out in the UK?
Mounjaro (tirzepatide) was approved by the MHRA and became available in the UK in 2023, following its earlier US approval. Today, it's one of two main prescription weight loss injections available to UK adults, alongside Wegovy (semaglutide). Access depends on whether you pursue the NHS route through specialist services or private prescription following an online clinical assessment. Understanding how to access Mounjaro — and the costs involved — helps you decide which route suits your situation.
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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.
How to Access Mounjaro in the UK: NHS vs Private
There are two main routes to Mounjaro in the UK: NHS specialist services and private prescription. Through the NHS, you'll need referral from your GP to a tier 3 specialist weight management service. Access varies significantly by region (ICB), and waiting lists can be lengthy — sometimes months or even years in some areas. NICE has approved tirzepatide (Mounjaro's active ingredient) for NHS use, but regional availability and funding differ widely.
The private route involves an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy. No NHS referral needed. A prescriber will assess your eligibility based on BMI and health factors, and if approved, issue a prescription. Private Mounjaro typically costs between £180–£320 per month depending on dose. You can check your eligibility using our free BMI calculator above — knowing your BMI helps you understand whether you meet the standard criteria (BMI 30+, or BMI 27+ with weight-related health conditions like hypertension or type 2 diabetes).
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.
What to Expect: Private Prescription Process & Cost Breakdown
The private Mounjaro process is straightforward: complete an online health questionnaire, consult with a prescriber (usually within 24 hours), and receive your prescription if suitable. The prescriber will discuss your medical history, current medications, and weight loss goals. Once approved, your Mounjaro KwikPen is dispatched to your home. Each pen contains four weekly doses, so a monthly supply is one pen.
Cost varies by dose: starter doses (2.5–5mg) typically cost less than maintenance doses (10–15mg). Some providers offer payment plans. Unlike the NHS route, private access means you control the timeline — no waiting lists. However, ongoing costs and responsibility for monitoring side effects rest with you, so ensure you have access to your GP for any health concerns during treatment.
- 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.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs £180–£320 per month depending on your dose. Starter doses are usually cheaper than maximum doses. Some providers offer discounts for upfront payment or multi-month packages. Always compare providers before committing.
Can I get Mounjaro on the NHS?
Yes, NICE has approved tirzepatide (Mounjaro's active ingredient) for NHS specialist weight management services. You'll need referral from your GP to a tier 3 service. Availability and waiting times vary significantly by region — contact your local weight management service to check access in your area.
How do I know if I'm eligible for Mounjaro?
You're typically eligible if you have a BMI of 30 or above, or BMI 27–29 with weight-related health conditions (type 2 diabetes, hypertension, sleep apnoea, cardiovascular disease). Check your BMI using our free calculator above, then consult your GP or a private prescriber for a full assessment.
What's the difference between Mounjaro and Wegovy in the UK?
Both are prescription-only weight loss injections available in the UK. Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro may deliver slightly higher average weight loss. Both are once-weekly injections with similar eligibility criteria and comparable private costs.
How long does private Mounjaro prescription take?
Most private providers offer consultation within 24 hours of your application. If approved, your prescription is issued immediately and your KwikPen is dispatched within 1–3 working days. You can often start treatment within a few days — much faster than NHS waiting lists in many regions.
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.