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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Tirzepatide for Weight Loss: UK Cost and Access Routes
Tirzepatide, marketed as Mounjaro, is a prescription weight loss injection available in the UK through both NHS specialist services and private prescribing. Cost and access vary significantly depending on which route you choose. This guide explains how much tirzepatide costs, eligibility criteria, and what the application process involves so you can make an informed decision about whether this weekly weight loss injection 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.
Private Tirzepatide Costs in the UK
Tirzepatide is available privately through UK-licensed prescribers and GPhC-registered pharmacies. Private costs typically range from £129 to £320 per month, depending on the dose you're on and which provider you use. Starting doses (2.5 mg) tend to be at the lower end, while higher maintenance doses (10–15 mg) cost more.
The cost covers the prescription assessment, the medication itself (four weekly injections), and support. Each KwikPen contains four doses, lasting one month. Many people remain on a maintenance dose for several months, so budgeting should account for ongoing monthly costs.
- Starting dose (2.5 mg): approximately £129–£160/month
- Mid-range doses (5–10 mg): approximately £180–£250/month
- Maximum dose (15 mg): approximately £280–£320/month
Prices vary between providers, so it's worth comparing before committing. Some providers offer discounts for longer commitments or prepayment.
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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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NHS vs Private Access: Which Route Is Right for You?
NHS route: Tirzepatide (Mounjaro) is available through NHS tier 3 specialist weight management services. Referral from your GP is required, and availability varies by region. Waiting lists can be several months to over a year in some areas. When available, NHS prescriptions are free, but access is limited and eligibility criteria are strict.
Private route: Faster access without NHS referral. You complete an online consultation with a UK-licensed prescriber, who assesses your eligibility based on your health history. If approved, your prescription is sent to a pharmacy and the medication is dispatched. This usually takes 1–2 weeks from consultation to first injection. Use our GLP-1 weight loss calculator to estimate potential outcomes, and track progress with our free progress tracker once you start treatment.
Online private consultations are straightforward: you answer health questions, provide your weight and height (use our free weight converter if you need to switch between stone and kilograms), and declare any medications or medical conditions. The prescriber reviews your information and decides whether tirzepatide is clinically appropriate. If yes, you'll receive a prescription; if no, they'll explain why and may suggest alternatives. Prescriptions are valid for 28 days, so you should arrange pharmacy dispatch quickly.
- 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.
Is tirzepatide available on the NHS in the UK?
Yes, tirzepatide (Mounjaro) is available through NHS specialist tier 3 weight management services. However, you need a GP referral, and availability varies by region. Many areas have long waiting lists. Private access is faster but involves out-of-pocket costs.
What is the typical cost of tirzepatide per month privately?
Private tirzepatide typically costs £129–£320 per month depending on dose. Starting doses (2.5 mg) are cheaper; higher maintenance doses cost more. Prices vary between providers, so compare before committing.
How long does it take to get tirzepatide privately?
Private access is usually quicker than NHS. After an online consultation with a UK-licensed prescriber, if approved, your prescription goes to a pharmacy within 1–2 weeks. NHS routes can take several months due to waiting lists.
What do I need to do to get a private prescription for tirzepatide?
Complete an online consultation with a UK-licensed prescriber. Answer health questions, provide your weight and height, and declare medications and medical conditions. If the prescriber approves, you'll receive a prescription sent to a GPhC-registered pharmacy for dispatch.
Can I get tirzepatide without a prescription in the UK?
No. Tirzepatide is prescription-only in the UK. It requires clinical assessment by a licensed prescriber before dispensing. Buying prescription medications without a valid prescription is illegal and unsafe.
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.