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 Get Mounjaro on the NHS in the UK
Getting Mounjaro (tirzepatide) on the NHS is possible, but access is limited to specialist weight management services rather than standard GP prescription. NICE has approved tirzepatide for NHS use, but availability varies significantly by region, and waiting lists can be long in many areas. This guide explains NHS eligibility, how to get referred, what to expect, and your private options if NHS access isn't available in your area.
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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 Access to Mounjaro — Eligibility and Referral Process
NICE approval: Tirzepatide (Mounjaro) is approved by NICE for use within NHS specialist weight management services, but it is not available as a standard GP prescription. Access is through tier 3 or tier 4 specialist multidisciplinary weight management services.
Who may be eligible: Adults with a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with weight-related health conditions (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply (BMI 27.5 or above).
How to access: Ask your GP for a referral to your local tier 3 weight management service. Your GP will assess whether referral is appropriate. Once referred, you will be assessed by the specialist team to determine if tirzepatide is suitable for you. Assessment includes medical history, current medications, and contraindication screening.
- Referral is the first step — GPs cannot prescribe Mounjaro directly
- Regional availability varies — not all areas have active weight management services
- Waiting times range from weeks to several months, depending on your region and service capacity
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 Access — Faster Alternative if NHS Waiting Times Are Long
If NHS access is not available in your area or waiting times are prohibitively long, tirzepatide is also available through private online prescribing services. A UK-licensed prescriber will assess your eligibility following an online consultation, and if appropriate, issue a prescription that can be dispensed by a GPhC-registered pharmacy. Private costs typically range from £150–£300 per month depending on dose, but you avoid NHS waiting lists. You can also use our free GLP-1 weight loss calculator to estimate potential weight loss with tirzepatide at different doses. Our BMI calculator helps confirm whether you meet the eligibility threshold of BMI 30 or above (or 27+ with health conditions).
- 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?
No. Mounjaro is not available as a standard GP prescription. It is only prescribed through NHS tier 3 specialist weight management services. Your GP can refer you to your local specialist service, but the specialist team must assess and prescribe it.
How long are NHS waiting lists for Mounjaro?
Waiting times vary significantly by region. Some areas have waiting lists of several weeks, while others may have delays of several months. Contact your local tier 3 weight management service for specific timescales in your area.
What if Mounjaro is not available in my NHS region?
Not all NHS regions currently offer Mounjaro through their weight management services. If it's unavailable locally, you can ask your GP about alternative NHS options (such as orlistat or liraglutide via Saxenda), or consider private prescribing as a faster alternative.
How is Mounjaro different from Wegovy for NHS access?
Both are licensed for weight management in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Both are accessed through NHS specialist services or private prescribing. Availability and approval timelines differ by region.
What happens during the NHS specialist assessment for Mounjaro?
The specialist team will review your medical history, current medications, weight, BMI, and weight-related health conditions. They will check for contraindications (such as thyroid cancer history or serious gastroparesis) and discuss whether Mounjaro is appropriate for you. If approved, treatment begins with dose titration starting at 2.5 mg weekly.
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.