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 to Buy Mounjaro Online in the UK
Mounjaro (tirzepatide) is a prescription-only weight loss injection available online in the UK through licensed prescribers and GPhC-registered pharmacies. Unlike unregulated online services, buying Mounjaro legally requires a clinical assessment from a UK-qualified prescriber who will determine whether this GIP and GLP-1 receptor agonist is appropriate for your health. This guide explains the legitimate routes to access Mounjaro online, costs, and what to expect from the prescription process. Our GLP-1 weight loss calculator can help you estimate potential results 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.
How to Access Mounjaro Online in the UK
There are two main routes to buy Mounjaro online in the UK: through the NHS or via private online prescription services.
NHS Route: Your GP can refer you to a tier 3 specialist weight management service if you meet eligibility criteria (BMI 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes or high blood pressure). NICE has approved tirzepatide for use within NHS specialist services. However, NHS availability varies significantly by region, and waiting lists can be lengthy — some areas have months-long delays. Once assessed by the specialist service, you may be prescribed Mounjaro and it will be dispensed through the NHS. Check your local integrated care board (ICB) website to find tier 3 services in your area.
Private Online Route: Multiple GPhC-registered online pharmacies offer Mounjaro following a consultation with a UK-licensed prescriber. You complete an online health questionnaire, a prescriber reviews your information and medical history, and if appropriate, issues a prescription. The pharmacy then dispatches your Mounjaro KwikPen to your address. This route does not require NHS referral and is typically faster than NHS services.
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.
What to Expect When Buying Mounjaro Online
When purchasing Mounjaro through a private online service, you'll be asked detailed health questions about your weight, BMI, any medical conditions, current medications, and weight loss history. The prescriber will assess whether Mounjaro is clinically appropriate — for example, it is not suitable if you are pregnant, breastfeeding, under 18, or have a personal or family history of medullary thyroid carcinoma.
If approved, your prescription will specify your starting dose (typically 2.5 mg) and the planned dose titration schedule — this means gradually increasing your dose weekly over several weeks to reach your maintenance dose. Mounjaro arrives as a KwikPen (pre-filled injection pen) with four weekly doses. Costs range from approximately £129–£320 per month depending on your dose level. Our progress tracker helps you log your weight loss journey alongside treatment.
- 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 it legal to buy Mounjaro online in the UK?
Yes, provided you buy from a GPhC-registered online pharmacy following a prescription from a UK-licensed prescriber. This is legal and regulated. Avoid any service that claims to sell Mounjaro without requiring a clinical assessment or prescription — these are illegal. Always verify the pharmacy is registered with the GPhC (General Pharmaceutical Council).
How much does Mounjaro cost when buying online privately?
Private costs typically range from £129–£320 per month depending on your dose. The starting dose (2.5 mg) is usually cheaper; the maximum dose (15 mg) costs more. Some services offer discounts for paying upfront for multiple pens. NHS Mounjaro is free, but access varies by region and waiting times can be substantial.
What is the difference between Mounjaro and Wegovy?
Both are prescription-only weight loss injections. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials show Mounjaro achieved slightly higher average weight loss (~21% vs ~15% body weight). Both are once-weekly injections. Your prescriber will help determine which is more suitable for you.
Can I get Mounjaro on the NHS?
Yes, through specialist tier 3 weight management services following GP referral. NICE has approved tirzepatide (Mounjaro) for NHS use. Eligibility typically requires a BMI of 30 or above (or 27–29.9 with weight-related health conditions). NHS availability and waiting times vary significantly by region — check with your local integrated care board for services and current waiting lists.
How long does it take to receive Mounjaro after ordering online?
Private online services typically dispatch within 2–7 working days of prescription approval, depending on the pharmacy. Delivery usually takes 1–3 working days via Royal Mail or courier. Total time from health questionnaire to receiving your first pen is often 7–10 days. NHS timescales depend on specialist service waiting lists, which can be several months in some areas.
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.