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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How to Access and Inject Mounjaro in the UK
Mounjaro (tirzepatide) is a prescription-only once-weekly injection available in the UK through both NHS specialist services and private online prescribing. Understanding your access options, costs, and how to inject Mounjaro safely is essential before starting treatment. This guide covers everything you need to know about getting Mounjaro in the UK, from eligibility assessment to injection technique and ongoing monitoring.
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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 Mounjaro Access and UK Costs
Private prescription Mounjaro is available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. Costs vary significantly by dose and provider, typically ranging from £129 to £320 per month depending on which KwikPen strength you're prescribed.
- Starting doses (2.5 mg) usually cost around £129–£150 per month
- Mid-range doses (5–7.5 mg) typically cost £180–£240 per month
- Higher doses (10–15 mg) generally cost £240–£320 per month
Each KwikPen contains four pre-filled doses (one month's supply). Private access is faster than NHS routes, with many pharmacies dispensing within 24–48 hours of prescription. Unlike Mounjaro vs Wegovy cost comparisons, tirzepatide pricing is relatively consistent across UK private providers, though shop around as some offer subscription discounts or loyalty schemes.
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 and What to Expect
NHS access to Mounjaro is through tier 3 specialist weight management services, typically requiring GP referral and assessment. Availability varies dramatically by region—some ICBs offer access within months, whilst others have waiting lists exceeding two years. NHS treatment is free once prescribed, but GPs cannot prescribe Mounjaro in primary care.
Private route process: You complete an online health questionnaire and consultation with a prescriber (usually within 24 hours). If approved, a prescription is sent to a GPhC pharmacy and dispensed with full dosage instructions and injection guidance. Most private providers offer follow-up consultations to monitor progress and manage dose titration safely. Use our GLP-1 weight loss calculator to estimate potential results at your expected dose.
- 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.
Do I need to be assessed before getting Mounjaro injections?
Yes. Whether accessing through NHS or private prescription, a licensed healthcare professional must assess your medical history, current medications, weight, BMI, and any contraindications before prescribing. This is a legal requirement and safety essential.
Can my GP prescribe Mounjaro directly?
No. NHS Mounjaro must be prescribed through tier 3 specialist weight management services, not primary care. Private Mounjaro requires an online assessment with a UK-licensed prescriber registered with the GMC or NMC.
How much does Mounjaro cost privately in the UK?
Private costs typically range from £129–£320 per month depending on your dose. Starting doses cost less than maximum doses. Some providers offer discounts for three or six-month subscriptions. Always check the full cost including any consultation fees.
How long does it take to get Mounjaro through NHS services?
This varies by region. Some areas process referrals within 3–6 months; others have longer waits. Contact your local ICB or ask your GP about waiting times in your area. Private access is typically faster (24–48 hours from prescription to dispensing).
What happens after I receive my Mounjaro prescription?
The pharmacy sends full injection instructions with your KwikPen. Most private providers offer follow-up consultations to monitor your progress, manage side effects, and adjust your dose according to NHS dosing schedules (minimum 4 weeks on each dose before escalating). Use our BMI calculator to track changes between doses.
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.