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 Weight Loss Calculator — UK Cost and Access
Mounjaro is a prescription-only weekly injection that may help support weight loss in adults meeting specific health criteria. If you're considering Mounjaro in the UK, you'll want to understand your access options — whether through NHS specialist services or private online prescribing — and what costs are involved. This guide explains both routes, typical pricing, and what to expect during the assessment process. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Private Prescription Cost and Access in the UK
Private access to Mounjaro in the UK is available through licensed online prescribers and GPhC-registered pharmacies without NHS referral. Typical costs range from £129 to £320 per month depending on your dose and the provider, with prices generally increasing as doses escalate from the starting 2.5 mg to the maximum 15 mg weekly injection.
- Each KwikPen contains 4 weekly doses — equivalent to one month's supply
- Online consultation fees typically range from £15 to £50, assessed once or at dose changes
- Prices vary between providers — comparing options is recommended
- Payment is usually per dose or per month, with some providers offering subscription discounts
- Prescription is issued only after a clinical assessment confirms you meet eligibility criteria
Private prescribing offers faster access than NHS routes, with many people receiving their first dose within 1–2 weeks of consultation. However, costs are not covered by the NHS, so this route requires private payment throughout.
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 — Understanding Your Options
The NHS route involves referral from your GP to a tier 3 specialist weight management service, where assessment and prescription happen under NHS supervision — potentially free at point of use, depending on your region. However, NHS availability is limited, with significant waiting lists in many areas (often months to years).
The private route bypasses NHS waiting lists entirely. You complete an online consultation with a UK-licensed prescriber, who assesses your health history, BMI, and any weight-related conditions. If approved, a prescription is issued to a pharmacy, and medication is dispensed for private payment. Both routes are legitimate; choice depends on your timeline, budget, and preference. Your GP can advise on NHS options in your area.
- 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 costs typically range from £129 to £320 per month depending on dose (starting 2.5 mg to maximum 15 mg weekly). Each KwikPen contains 4 weeks' worth of weekly injections. Online consultation fees are usually £15–£50, assessed during initial consultation and any dose changes. Prices vary between providers, so comparing options is worthwhile.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is available on the NHS through specialist tier 3 weight management services following NICE approval. However, access requires GP referral and assessment by a specialist service. Availability and waiting times vary significantly by region (ICB). Many areas have waiting lists of several months to years, making private access quicker for many people.
What's the difference between NHS and private Mounjaro prescriptions?
NHS prescriptions are free at point of use (or on standard prescription charge) but involve referral, assessment, and potential waiting lists. Private prescriptions require payment (£129–£320/month) but offer faster access (1–2 weeks) and no NHS referral needed. Both require a prescription from a UK-licensed prescriber and clinical assessment to confirm eligibility.
How does the online prescription process work for Mounjaro?
You complete an online health questionnaire covering your medical history, current medications, weight, height, and any weight-related health conditions. A UK-licensed prescriber reviews this and conducts a virtual consultation. If you meet eligibility criteria (BMI ≥30, or ≥27 with health conditions), a prescription is issued and sent to a GPhC-registered pharmacy, which dispenses your KwikPen.
What eligibility criteria must I meet for Mounjaro?
UK eligibility requires a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, high blood pressure, abnormal cholesterol, sleep apnoea, or cardiovascular disease). South Asian, Chinese, Black African, and Black Caribbean adults may have lower BMI thresholds (≥27.5). Your prescriber will assess these criteria during consultation.
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.