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 Get Mounjaro On Prescription In The UK
Getting Mounjaro on prescription in the UK involves two distinct routes: through the NHS specialist weight management services or via private online prescribing. Mounjaro (tirzepatide) is a prescription-only medicine available to adults meeting specific eligibility criteria. The NHS route typically involves referral through your GP, whilst private access bypasses the NHS wait and requires an online clinical assessment. Both pathways are legitimate, and your choice depends on availability in your area, waiting times, and personal circumstances.
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.
NHS Route: Specialist Weight Management Services
The NHS route to Mounjaro requires referral to a tier 3 or tier 4 specialist weight management service. Your GP cannot prescribe Mounjaro directly in most cases — you need to be referred to your local integrated care board's (ICB) specialist service. Eligibility for NHS prescription includes a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, prediabetes, high blood pressure, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may be eligible at lower BMI thresholds.
Once referred, the specialist team will conduct a comprehensive assessment including medical history, current medications, and contraindications. If approved, Mounjaro will be prescribed with ongoing monitoring. NICE has approved tirzepatide for NHS use, but availability varies significantly by region. Waiting lists for tier 3 services can be lengthy — some areas have waits of 12–24 months. Use our free BMI calculator above to check whether you might meet the initial BMI threshold for NHS eligibility.
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 Prescribing Pathway
The private route to Mounjaro involves an online consultation with a UK-licensed prescriber and dispensing through a GPhC-registered pharmacy. This pathway does not require NHS referral or your GP's involvement. You complete an online health questionnaire, have a consultation (usually video or phone) with a registered healthcare professional, and receive a prescription if clinically appropriate. The prescriber will assess your BMI, medical history, current medications, and any contraindications — the same eligibility criteria apply as NHS.
Private Mounjaro is available at different doses (2.5 mg to 15 mg once weekly). Costs range from approximately £129–£320 per month depending on the dose and provider. Private prescribing can provide access within days or weeks, compared to months on NHS waiting lists. Try our GLP-1 weight loss calculator to project potential outcomes and explore whether this investment aligns with your weight loss goals.
- 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 my GP prescribe Mounjaro directly on the NHS?
In most cases, no. Your GP must refer you to a specialist tier 3 or tier 4 weight management service. Your GP cannot initiate Mounjaro directly. Specialist services conduct formal assessment before prescription. Some CCGs may have different arrangements, so ask your GP about your local pathway if unsure.
How long does the NHS referral process typically take?
Referral to specialist assessment usually takes 4–12 weeks depending on your ICB. However, waiting lists for treatment can be 12–24 months or longer in many areas. Some regions have shorter waits. Ask your GP about current wait times in your area before requesting referral.
What is the difference between Mounjaro and Wegovy on prescription?
Both are GLP-1-based weight loss injections licensed in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with a maximum dose of 15 mg weekly. Wegovy (semaglutide) is a GLP-1-only agonist with a maximum dose of 2.4 mg weekly. Clinical trials showed slightly different average weight loss results, though individual outcomes vary significantly.
Am I eligible for Mounjaro if my BMI is 27?
You may be eligible if your BMI is 27–29.9 AND you have a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply. Use our BMI calculator above to check your exact BMI category.
What does a private Mounjaro consultation involve?
You complete a detailed health questionnaire covering medical history, current medications, allergies, and contraindications. A UK-licensed prescriber (usually a doctor or nurse prescriber) reviews your information and may conduct a brief video or phone consultation. If approved, a prescription is issued to a GPhC-registered pharmacy for dispensing. The whole process typically takes 24–48 hours.
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.