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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Starting Mounjaro in the UK — Cost and Access Guide
Beginning Mounjaro treatment involves understanding both the financial commitment and the access route available to you in the UK. Whether you're exploring NHS specialist services or private prescription options, the cost and process differ significantly. This guide explains your options, what day 1 costs look like, and how to navigate the UK healthcare system to start this tirzepatide weight management journey.
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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.
Mounjaro Cost and Access in the UK Private Route
Private prescription costs for Mounjaro in the UK typically range from £129 to £320 per month depending on your dose and provider. The starting dose (2.5 mg) usually costs less than maximum maintenance doses (15 mg). Each KwikPen contains four weekly injections, so costs shown are usually per monthly supply.
- Starting dose 2.5 mg: approximately £129–£160 per month
- Mid-range doses (5–10 mg): approximately £180–£240 per month
- Maximum dose 15 mg: approximately £280–£320 per month
Private access requires an online clinical assessment with a UK-licensed prescriber following GMC or NMC registration. If approved, your prescription is dispensed by a GPhC-registered pharmacy. This route avoids NHS waiting lists but requires you to pay the full cost. Costs may vary between providers, so comparing options is worthwhile. You can use our free GLP-1 weight loss calculator to estimate projected results at different doses before committing financially.
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 to Start Mounjaro
NHS access is free but involves a longer process. NICE has approved tirzepatide for specialist weight management services, meaning access is through tier 3 or tier 4 NHS specialist centres following GP referral. Availability varies dramatically by region (ICB), and waiting lists in many areas extend many months. On day 1 of NHS treatment, there is no cost to you—prescriptions are dispensed free under the NHS.
Private access is faster—typically within 1–2 weeks of your initial consultation—but you pay upfront. Day 1 cost includes your first KwikPen. The online consultation process takes 10–15 minutes; a prescriber reviews your eligibility based on BMI and health history using our BMI calculator standards (BMI ≥30 or ≥27 with weight-related conditions), checks contraindications, and issues a prescription if appropriate. Payment is arranged before dispensing.
NHS access is free but involves a longer process. NICE has approved tirzepatide for specialist weight management services, meaning access is through tier 3 or tier 4 NHS specialist centres following GP referral. Availability varies dramatically by region (ICB), and waiting lists in many areas extend many months. On day 1 of NHS treatment, there is no cost to you—prescriptions are dispensed free under the NHS.
Private access is faster—typically within 1–2 weeks of your initial consultation—but you pay upfront. Day 1 cost includes your first KwikPen. The online consultation process takes 10–15 minutes; a prescriber reviews your eligibility based on BMI and health history using our BMI calculator standards (BMI ≥30 or ≥27 with weight-related conditions), checks contraindications, and issues a prescription if appropriate. Payment is arranged before dispensing.
- 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 on day 1 in the UK privately?
Private day 1 cost is your first KwikPen supply, typically £129–£320 depending on starting dose. The 2.5 mg starting dose costs around £129–£160. This covers your first four weekly injections. Each KwikPen is pre-filled with one month's supply (four pens). Payment is required before dispensing following your online consultation approval.
Can I get Mounjaro free on the NHS?
Yes, Mounjaro is free on the NHS through specialist weight management services (tier 3/4), but access requires GP referral and assessment by a specialist centre. Waiting times vary by region from weeks to many months depending on your local ICB. Once approved, all prescriptions are dispensed free, with no day 1 cost to you.
What happens during an online Mounjaro consultation?
An online consultation with a UK-licensed prescriber takes 10–15 minutes. They review your medical history, current medications, BMI, and weight-related health conditions. They check for contraindications (allergies, severe gastroparesis, pregnancy plans). If approved, a prescription is issued same-day or within 24 hours, then dispensed by a GPhC-registered pharmacy.
Is Mounjaro cost worth it compared to weight loss alternatives?
That's a personal decision. At £129–£320 monthly, Mounjaro is a significant investment. Clinical trials showed average weight loss of 15–21% of body weight, though results vary. Weigh this against NHS lifestyle programmes (free) or other approaches. Our GLP-1 weight loss calculator can help you project potential outcomes before committing.
What's the difference between Mounjaro and Wegovy cost-wise?
Both are similarly priced (approximately £129–£320 monthly in the UK), though Mounjaro uses a different mechanism (dual GIP/GLP-1 vs Wegovy's GLP-1 only). Mounjaro has higher maximum doses (15 mg vs Wegovy's 2.4 mg), so per-dose pricing may differ. Check current provider pricing as costs fluctuate and vary between suppliers.
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.