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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Black Friday Mounjaro — UK Cost & Access Guide
Mounjaro (tirzepatide) is a prescription-only weight management injection that many UK adults explore, especially during sales events like Black Friday. If you're considering Mounjaro and wondering about cost, eligibility, and how to access it safely in the UK, this guide covers what you need to know about prescription routes, pricing, and what the NHS offers versus private options.
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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.
How Much Does Mounjaro Cost in the UK?
Mounjaro pricing in the UK varies significantly depending on whether you access it through the NHS or private online prescribing. Private costs typically range from £129 to £320 per month depending on your dose, with higher doses (15mg KwikPen) at the premium end. A full four-week supply of a starter dose (2.5mg) generally costs less than a maintenance or maximum dose. Pricing during promotional periods like Black Friday may offer modest discounts, but significant reductions are uncommon because tirzepatide is a prescription medicine subject to strict MHRA regulations. When comparing costs, always check that the provider is GPhC-registered and that a UK-licensed prescriber has conducted a proper clinical assessment. Never base your choice purely on price — the cheapest option may not include proper follow-up support or dose escalation guidance. NHS access is free if eligible, but involves referral to specialist tier 3 weight management services with potential waiting lists.
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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 vs Private Access Routes
The NHS provides Mounjaro free if you meet eligibility criteria (typically BMI 30+ or 27+ with weight-related health conditions) and are referred to a specialist weight management service. However, NHS access varies by region and waiting lists can be lengthy. Private online prescribing offers faster access without NHS referral — you complete an online consultation, a licensed prescriber assesses your suitability, and a GPhC-registered pharmacy dispenses your prescription. This route costs £129–£320 monthly depending on dose. Both routes require a genuine clinical assessment; neither offers weight loss medication without proper evaluation. Our GLP-1 weight loss calculator can help you understand potential dose needs before consulting a prescriber, and your BMI calculator result (available above) is useful context for your assessment.
- 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.
Will I find Black Friday discounts on Mounjaro in the UK?
Black Friday offers on prescription medications are uncommon and typically modest, as tirzepatide is subject to MHRA regulation. Legitimate UK pharmacies rarely discount prescription medicines dramatically. Focus on finding a reputable GPhC-registered provider rather than chasing the lowest price — proper clinical support is worth more than a small saving.
Is Mounjaro cheaper on the NHS than private?
Yes — Mounjaro is free on the NHS if you're eligible and referred through your GP to a specialist weight management service. Private costs £129–£320 monthly. The trade-off is that NHS access typically involves longer waiting lists, while private access is faster.
What should I check before buying Mounjaro online?
Always verify the pharmacy is GPhC-registered (you can check on the General Pharmaceutical Council website). Confirm a UK-licensed prescriber conducts a proper clinical assessment — not just a quick form. Avoid providers offering medication without assessment, as this is unsafe and potentially illegal.
How do I get a Mounjaro prescription on the NHS?
Speak to your GP, who can refer you to your local tier 3 specialist weight management service. Eligibility typically requires BMI 30+ or BMI 27+ with weight-related health conditions. Assessment and prescription happen through the specialist service, not your GP.
Does my dose affect the monthly cost?
Yes — higher doses (15mg KwikPen) cost more than lower doses (2.5–5mg starter doses). A full four-week supply at maximum dose may cost 20–30% more than a starter dose, though some providers offer fixed-price dose escalation packages.
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.