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
Free tracker included with every download this week
How Much Does Mounjaro 2.5mg Cost in the UK?
Mounjaro 2.5mg is the starting dose of tirzepatide, and costs vary significantly between NHS and private routes in the UK. The 2.5mg dose is typically used for 4 weeks as part of the dose titration schedule before escalating to higher doses. Private prescription costs range from approximately £130–£180 per KwikPen (4-week supply), though prices vary by provider. NHS access is free but requires referral to a specialist weight management service and can involve lengthy waiting lists. Understanding your options helps you choose the most suitable route for your circumstances.
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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 Prescription Costs for Mounjaro 2.5mg in the UK
Private prescription costs for Mounjaro 2.5mg typically range from £130–£180 per KwikPen, though individual providers may vary. Each KwikPen contains four weekly injections, so this is your monthly cost. As the starting dose, you'll remain on 2.5mg for weeks 1–4 before your prescriber assesses whether to escalate to the next dose. Private access is through an online consultation with a UK-licensed prescriber, who will assess your eligibility before issuing a prescription. This route offers flexibility and shorter waiting times compared to NHS services, though you pay the full cost yourself. Prices may differ between providers, so comparing options is worthwhile. The KwikPen requires refrigeration (2–8°C unopened, or up to 30 days at room temperature after first use) and must be disposed of 30 days after first use.
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 Routes — How to Access Mounjaro 2.5mg
NHS access to Mounjaro is free but requires a referral from your GP to a specialist tier 3 or tier 4 weight management service. NICE has approved tirzepatide for NHS use, but availability depends on your local ICB (Integrated Care Board), and waiting lists can extend several months to years in many areas. Private access is faster: book an online consultation with a UK-licensed prescriber, provide health information, and receive a prescription within 24–48 hours if approved. The prescription is dispensed by a GPhC-registered pharmacy. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses, which may help inform your decision-making. Both routes require a prescription and clinical assessment—Mounjaro is not available over-the-counter.
- 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 Mounjaro 2.5mg available on the NHS?
Yes, Mounjaro (tirzepatide) is approved by NICE for NHS use, but access is through specialist weight management services via GP referral. Availability varies by region and waiting lists can be lengthy. Private prescription is a faster alternative if you wish to start immediately.
How long will one Mounjaro 2.5mg KwikPen last?
One KwikPen contains four weekly injections, so it lasts 4 weeks. At 2.5mg per week, you'll use one pen during your initial dose titration phase before potentially moving to the next dose level.
What is included in the Mounjaro 2.5mg cost?
The private cost typically covers the KwikPen, the prescription fee, and pharmacy dispensing. However, some providers bundle these differently, so check what's included. The prescription itself may have a separate consultation fee, usually £15–£40.
Can I get Mounjaro 2.5mg cheaper through the NHS?
NHS Mounjaro is free once you access specialist services, making it much cheaper than private if you qualify and can access a service. However, NHS waiting lists can be months or years long in many areas, whereas private routes offer quicker access for a cost.
How does Mounjaro 2.5mg cost compare to Wegovy?
Mounjaro 2.5mg starting dose is generally similar in private cost to Wegovy starting doses (approximately £130–£180). However, Mounjaro and Wegovy are different medications with different mechanisms—Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is GLP-1 only. Your prescriber will assess which is appropriate for you.
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.