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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Where to Inject Mounjaro — UK Access & Cost Guide
Mounjaro is injected once weekly into specific areas of your body, and accessing it in the UK depends on whether you go through the NHS or private prescription route. The cost, waiting times, and process differ significantly between these two pathways. This guide explains where to inject, what UK access looks like, and what you can expect from getting a prescription.
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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 Injection Sites & Private Access Costs in the UK
Mounjaro (tirzepatide) is a once-weekly weight loss injection delivered using a pre-filled KwikPen device. You can inject into three main areas: your stomach (abdomen), upper thigh, or upper arm. Most people choose the stomach or thigh as these are easiest to access alone. The upper arm requires assistance from another person. You should rotate your injection site each week to avoid tissue irritation or lipohypertrophy (thickened fatty tissue).
In the UK private prescription route, Mounjaro costs range from approximately £129 to £320 per month depending on your dose and the provider. Most private providers dispense a 4-week supply (one KwikPen containing 4 doses). Your dose typically increases over 12–20 weeks from 2.5 mg to your target maintenance dose (often 10 or 15 mg). Higher doses cost more. Costs are approximately: 2.5–5 mg around £129–£180; 7.5–10 mg around £200–£250; 12.5–15 mg around £280–£320 per month. These are typical ranges — prices vary between providers.
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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 — What to Expect
NHS access: NICE has approved tirzepatide for NHS use within specialist tier 3 weight management services. You must be referred by your GP to a local specialist weight management service. NHS services typically require you to have a BMI ≥30 (or ≥27 with weight-related health conditions) and often require you to have tried lifestyle changes first. Waiting lists vary by region (ICB) — some areas have waiting times of 6 months to 2+ years. Once approved, Mounjaro is free on the NHS.
Private access: You complete an online consultation with a UK-licensed prescriber (usually via a GPhC-registered provider). The process typically takes 24–48 hours. You'll answer health questions about your medical history, current medications, and weight management goals. If approved, a prescription is issued and dispensed by a pharmacy. No referral needed. You pay for each month's supply upfront.
The online consultation process involves filling out a detailed health questionnaire covering: current weight and height (to calculate BMI), medical history, medications, allergies, family health history, and any previous weight loss attempts. The prescriber reviews this information to assess suitability. They may ask follow-up questions via secure messaging. If Mounjaro is appropriate for you, a prescription is issued to a GPhC-registered pharmacy. Use our free GLP-1 weight loss calculator to estimate potential results at different doses, which may help inform your discussion with the prescriber. Most private providers offer ongoing support, including dose adjustment advice and side effect management, though this varies by service.
- 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.
Can I inject Mounjaro anywhere on my body?
No. Mounjaro must be injected into specific areas: stomach (abdomen), upper thigh, or upper arm. These subcutaneous injection sites have enough fatty tissue for safe injection. Rotate sites weekly to prevent irritation or lipohypertrophy. Never inject into muscle, vein, or scarred areas. Always follow your prescriber's instructions.
How much does Mounjaro cost privately in the UK per year?
Private Mounjaro costs approximately £1,500–£3,800 per year depending on your maintenance dose. Starting doses (2.5–5 mg) cost around £150–£220/month; higher doses (12.5–15 mg) cost £280–£320/month. Prices vary between providers. Some offer multi-month discounts. Always check current pricing with your chosen provider.
How long is the NHS waiting list for Mounjaro?
NHS waiting times vary significantly by region (ICB). Some areas have waiting times of 6–12 months; others exceed 2 years. This depends on local service capacity and demand. Your GP can tell you the expected waiting time in your area when they refer you to the specialist weight management service.
What happens during an online Mounjaro consultation?
You complete a detailed health questionnaire covering weight, height, medical history, medications, and allergies. A UK-licensed prescriber reviews this. They may ask follow-up questions via secure messaging. If approved, a prescription is issued to a GPhC-registered pharmacy. The process typically takes 24–48 hours. You'll need to provide valid ID and proof of address.
Can I switch from NHS to private Mounjaro if the waiting list is too long?
Yes. Many people start private Mounjaro while on an NHS waiting list, then transition to NHS once approved. Some continue privately if they prefer the flexibility and faster access. Discuss with your GP if you're considering private treatment — they can provide clinical guidance and monitor your progress.
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.