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 Do You Get Mounjaro in the UK?
Getting Mounjaro (tirzepatide) in the UK requires a prescription from a licensed healthcare professional following a clinical assessment. You can access this weight management injection through either NHS specialist services or private online prescribing. Both routes require you to meet specific eligibility criteria based on your BMI and health status. This guide explains the exact pathways, what to expect, and how long the process typically takes. Use our free BMI calculator to check whether you might meet the eligibility thresholds before approaching your GP or a private prescriber.
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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.
NHS Route: Accessing Mounjaro Through Specialist Services
NHS access to Mounjaro is through tier 3 specialist weight management services, not standard GP prescription. Here's the process:
- Ask your GP for a referral to your local NHS weight management service (this is a specialist tier 3 or 4 service, not your standard GP practice)
- Your GP will review your BMI, health conditions, and weight history to decide if referral is appropriate
- Once referred, you'll be assessed by a multidisciplinary team (dietitian, nurse, sometimes psychologist) at the specialist service
- If you're deemed eligible, the specialist team will prescribe Mounjaro and manage your ongoing care
- Important: NHS availability varies dramatically by region. Some areas have waiting lists of 6–18 months; others may not have specialist services available
Check your local Integrated Care Board (ICB) website to find your nearest NHS weight management service and expected waiting times.
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.
Private Route: Online Prescription and Pharmacy Access
Private prescribing offers faster access without NHS referral. The private pathway works like this:
- Complete a clinical assessment with a UK-licensed prescriber (usually online consultation, typically 10–15 minutes)
- The prescriber reviews your weight, BMI, health conditions, medications, and contraindications
- If approved, a prescription is issued to a GPhC-registered pharmacy
- Mounjaro is dispensed and delivered (usually within 2–3 working days)
- You manage your own dose titration, following the standard schedule from 2.5mg upwards
- Some providers offer ongoing prescriber support; others offer GP liaison letters for your records
Private costs range from approximately £129–£320 per month depending on dose. No NHS involvement required.
- 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.
What's the difference between NHS and private Mounjaro access?
NHS route goes through specialist tier 3 services and is free but has long waiting lists (often 6–18 months depending on region). Private route involves online clinical assessment with a licensed prescriber and faster access (days to weeks) but costs approximately £129–£320 monthly depending on dose. Both require clinical assessment and eligibility checks.
Do I need a GP referral to get Mounjaro on the NHS?
Yes, you'll need your GP to refer you to your local NHS specialist weight management service. Your GP will review whether referral is appropriate based on your BMI and health. However, private prescribing does not require NHS involvement or GP referral—just a direct clinical assessment with a private prescriber.
Who is eligible for Mounjaro in the UK?
Adults with BMI 30 or above are generally eligible. Those with BMI 27–29.9 may be eligible if you have weight-related health conditions (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease). South Asian, Chinese, Black African, and Black Caribbean adults have lower thresholds. A prescriber will assess your individual eligibility.
How long does the Mounjaro prescription process take?
NHS route: referral to assessment can take 3–18 months depending on your region and local waiting lists. Private route: typically 1–5 working days from consultation to prescription issued. Once you have a prescription, the KwikPen is usually delivered within 2–3 working days.
What happens after I'm prescribed Mounjaro?
You'll start at 2.5mg once weekly, increasing by 2.5mg every 4 weeks until you reach an effective dose (typically 5–15mg). You inject yourself using the pre-filled KwikPen. You'll need ongoing monitoring—NHS services provide this; private providers may offer support or recommend GP liaison. Use our GLP-1 weight loss calculator to see projected outcomes, and our progress tracker to log your weekly results. ```
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.