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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Who Qualifies for Mounjaro in the UK?
Mounjaro eligibility in the UK depends on your BMI, health conditions, and whether you access it through the NHS or privately. Most adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure, may qualify. Access routes differ significantly: NHS prescriptions come through specialist weight management services (often with lengthy waiting lists), whilst private prescriptions are available through online clinical assessments without NHS referral. Understanding your options and costs can help you decide the best route for 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.
Mounjaro Private Prescription Costs in the UK
Private Mounjaro costs vary by dose and provider, with most KwikPens priced between £129 and £320 per month. Starter doses (2.5 mg) are typically at the lower end, whilst maintenance and higher doses (10–15 mg) cost more. A standard KwikPen contains four weeks' supply of your current dose. Many private providers offer tirzepatide (the generic term for Mounjaro) at similar prices to the branded version.
- 2.5 mg dose: approximately £129–£160 per pen (4 weeks)
- 5 mg dose: approximately £150–£180 per pen
- 10 mg dose: approximately £200–£250 per pen
- 15 mg dose: approximately £280–£320 per pen
Prices do not include any clinical consultation fees, which typically range from £50–£150 for the initial assessment. Many providers bundle consultation with the first prescription or offer monthly subscription discounts.
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.
NHS vs Private Access: What to Expect
NHS route: Your GP can refer you to a tier 3 specialist weight management service if you meet criteria. However, Mounjaro NICE guidance approval has not resulted in widespread immediate availability—most regions have significant waiting lists, sometimes 6–12 months or longer. Once assessed by the specialist service, Mounjaro is prescribed free on the NHS, but dose titration occurs within their timescale.
Private route: A UK-licensed prescriber conducts an online clinical assessment, usually responding within 24 hours. If approved, your Mounjaro UK prescription is issued and dispensed by a GPhC-registered pharmacy. You control the pace and can access higher doses quickly. No GP referral needed—access is immediate, but costs are your responsibility.
Both routes require genuine clinical assessment. Mounjaro vs Wegovy decisions are often made during your assessment based on your medical history.
- 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 BMI do I need to qualify for Mounjaro in the UK?
Most adults with a BMI of 30 or above qualify. If your BMI is 27–29.9, you may qualify if you have a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply—starting from BMI 27.5.
How much does Mounjaro cost privately per month?
Private costs range from approximately £129 per month for starter doses (2.5 mg) to £320 for the maximum dose (15 mg). Each KwikPen contains four weeks' supply. Add £50–£150 for an initial clinical assessment. Many providers offer subscription discounts or bundle consultation with the first prescription.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region. Many areas have waiting lists of 6–12 months or longer for specialist tier 3 weight management services. Once referred by your GP and assessed, Mounjaro is free on the NHS—but availability depends on your local ICB (Integrated Care Board) and service capacity.
Can I get a private Mounjaro prescription without seeing my GP first?
Yes. Private online prescribing does not require a GP referral. A UK-licensed prescriber conducts an online clinical assessment, reviews your medical history, and issues a prescription if appropriate. The process typically takes 24 hours, and the prescription is dispensed by a GPhC-registered pharmacy.
Does private Mounjaro cost include the clinical assessment?
Not always. Most providers charge £50–£150 for the initial clinical assessment separately, though some bundle this with your first prescription. Subscription models may offer discounts on ongoing doses. Always check the full cost breakdown before committing—assessment fees and prescription costs are separate.
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.