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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How Much Does 12.5 Mg Mounjaro Cost in the UK?
The 12.5 mg dose of Mounjaro (tirzepatide) is the second-highest maintenance dose available in the UK and typically costs between £180–£250 per month through private online prescription services. Access to Mounjaro depends on whether you pursue an NHS specialist referral or private prescription route, each with different timelines, costs, and eligibility assessments. Understanding your options helps you make an informed decision about treatment.
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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.
Private Mounjaro Costs and Prescription Access
Mounjaro at 12.5 mg costs approximately £180–£250 per month via GPhC-registered online pharmacies in the UK, though prices vary between providers. Each KwikPen contains 4 doses (4 weeks supply), so monthly costs reflect a full supply. Costs may be higher or lower depending on your chosen provider and any promotional offers.
To access Mounjaro privately, you'll undergo an online clinical assessment with a UK-licensed prescriber who will review your medical history, BMI, weight-related health conditions, current medications, and any contraindications. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. The entire process typically takes 24–48 hours from initial consultation to delivery.
Most users start at 2.5 mg and escalate gradually every 4 weeks through 5 mg, 7.5 mg, 10 mg, and 15 mg before reaching 12.5 mg (if clinically appropriate). The dose titration schedule means you won't immediately pay for 12.5 mg—costs build as your dose increases.
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 Route: Access and Wait Times
NHS access to Mounjaro is through tier 3 specialist weight management services via GP referral. NICE has approved tirzepatide for NHS use, but availability varies significantly by region (ICB). Wait times can be several months to over a year in many areas, and prescribing is often limited to higher BMI thresholds or specific comorbidities.
Private access is immediate once you pass clinical assessment—no GP referral needed. You pay the full cost per prescription, typically £180–£250 monthly depending on dose and provider. Private consultations take 24–48 hours versus NHS waits of months. Compare both routes: NHS is free but involves waits; private is fast but costs apply. Use our GLP-1 weight loss calculator to estimate potential weight loss on 12.5 mg, and our BMI calculator to confirm your eligibility before starting any consultation.
- 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 12.5 mg Mounjaro the maximum dose available in the UK?
No. 12.5 mg is the second-highest dose; 15 mg is the maximum UK-licensed dose for tirzepatide (Mounjaro). Your prescriber determines the appropriate dose based on your response, weight loss progress, and tolerance of side effects. Most users stabilise at 10 mg or 15 mg.
Can I get Mounjaro on the NHS at 12.5 mg?
Possibly, through NHS tier 3 specialist weight management services. However, NHS access involves GP referral, specialist assessment, and variable waiting times (weeks to months). Eligibility and prescribing vary by region and ICB commissioning.
What's included in the £180–£250 monthly cost?
The cost covers a full month's supply (1 KwikPen = 4 doses for 4 weeks) at your prescribed dose. This does not include the online consultation fee (often £30–£50 one-off), but subsequent refills do not repeat the consultation charge.
Does Mounjaro cost more at higher doses?
Yes. Each incremental dose increase costs more. 2.5–5 mg is cheaper than 10–12.5 mg, which costs less than 15 mg. Pricing reflects the dose concentration per pen, so your monthly cost builds as you titrate upward.
Can I switch between Mounjaro and Wegovy to save money?
Both are prescription-only and should only be switched under prescriber guidance. Tirzepatide (Mounjaro) and semaglutide (Wegovy) have different mechanisms and costs. Never switch without clinical advice, as individual tolerability and efficacy differ between the two.
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.