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 Pen Dosage: UK Costs and How to Access
Mounjaro (tirzepatide) is available in the UK as a once-weekly injectable pen called a KwikPen, starting at 2.5 mg and scaling up to 15 mg. If you're considering this prescription weight loss medication, understanding the cost and access routes — both NHS and private — is essential. This guide explains UK pricing, eligibility, and how to get a prescription through either pathway.
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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 Mounjaro Costs in the UK
Private prescription costs for Mounjaro in the UK typically range from £129 to £320 per month, depending on your dose and the provider you choose. These prices cover the medication plus the clinical consultation assessment required before dispensing.
- Lower doses (2.5–5 mg): approximately £129–£180 per month
- Mid-range doses (7.5–10 mg): approximately £180–£240 per month
- Higher doses (12.5–15 mg): approximately £240–£320 per month
Each KwikPen contains four weekly doses (one month's supply). Private access through a GPhC-registered online pharmacy does not require an NHS referral — you can access prescription weight loss support without waiting for specialist NHS services. A UK-licensed prescriber reviews your health information through an online consultation and issues a prescription if appropriate. You can start immediately upon prescription approval, making private access faster than NHS routes in most regions.
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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 Access vs Private: Which Route Is Right for You?
NHS access is free at the point of care once prescribed, but requires referral to a tier 3 specialist weight management service through your GP. Waiting lists for NHS specialist services vary by region and can range from weeks to over a year in some areas. Private access is faster — you can get a prescription within 24–48 hours — but costs apply. Both routes require clinical assessment to confirm you meet eligibility criteria (BMI ≥30, or ≥27 with weight-related health conditions). Your GP can advise on NHS availability in your area and discuss whether private options suit your circumstances. Try our GLP-1 weight loss calculator to explore potential dosing and projected outcomes, and use the BMI calculator to confirm your eligibility before pursuing either route.
- 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 a Mounjaro KwikPen?
A KwikPen is Mounjaro's pre-filled injection device. Each pen contains four weekly doses (one month's supply). It's stored in the fridge unopened and at room temperature for up to 30 days after first use. The pen is colour-coded by dose strength, making it easy to identify your current dose level.
How long does one Mounjaro pen last?
One KwikPen contains exactly four weekly doses, so it lasts one month. You inject once per week. If you're escalating doses (increasing every 4 weeks), you'll need a new pen each month until you reach your maintenance dose, typically 15 mg.
Does the NHS cover Mounjaro costs?
Yes, once prescribed through an NHS tier 3 specialist weight management service, Mounjaro is free. However, NHS access requires GP referral and eligibility assessment. Access and waiting times vary significantly by region — ask your GP about availability in your area.
Can I get Mounjaro privately without seeing my GP first?
Yes. Private prescription access doesn't require GP involvement. You complete an online health questionnaire, a UK-licensed prescriber reviews it, and if approved, you receive a prescription from a GPhC-registered pharmacy. No NHS referral needed.
Is tirzepatide the same as Mounjaro?
Tirzepatide is the active ingredient in Mounjaro. Mounjaro is the brand name. Both terms refer to the same medication. Mounjaro is currently the only UK-licensed tirzepatide product for weight management — it's a dual GIP and GLP-1 receptor agonist, distinct from single GLP-1 medications like Wegovy.
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.