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 in the UK is possible but involves a specific referral pathway through specialist weight management services. Unlike private prescribing, NHS access requires assessment by a tier 3 or tier 4 specialist team rather than your GP alone. This guide explains NHS eligibility criteria, the referral process, what to expect, and realistic timescales. Access varies significantly by region—some areas have established programmes, whilst others have limited availability or waiting lists extending several months.
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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.
NHS Eligibility Criteria and Referral Pathway
You may be eligible for Mounjaro through the NHS if you have:
- A BMI of 30 kg/m² or above, or
- A BMI of 27–29.9 kg/m² alongside at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds (27.5+) may apply due to higher metabolic risk at lower weights.
The NHS referral process involves: discussing weight management options with your GP, who assesses whether you meet criteria and refers you to a specialist tier 3 weight management service. These are regional multidisciplinary teams led by consultants. A specialist clinician then conducts a full clinical assessment—reviewing your weight history, medical conditions, medications, and psychological readiness—before deciding whether Mounjaro is appropriate. Use our free BMI calculator to check where you fall against NHS thresholds.
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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 You Need to Know
The key difference is availability and waiting times. NHS Mounjaro is prescribed only through specialist tier 3 services. NICE has approved tirzepatide for NHS use in weight management, but access depends on your regional Integrated Care Board (ICB) funding and service capacity. Many areas have waiting lists of 6–18 months or longer.
Private prescribing is faster—typically 1–2 weeks from assessment to first dose—but costs approximately £150–£300 per month depending on your dose. Both routes require a valid prescription from a UK-licensed prescriber and clinical assessment. Your GP can discuss which route suits your circumstances and urgency. Calculate your projected weight loss using our free GLP-1 weight loss calculator to understand potential outcomes.
- 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.
How long does it take to get Mounjaro on the NHS?
Timescales vary by region. Initial GP appointment and referral typically take 2–4 weeks. Specialist assessment may involve a 3–12 month wait depending on your local tier 3 service capacity. Once approved, you'll start on 2.5 mg weekly, with dose increases every 4 weeks up to your optimal maintenance dose.
Will my GP prescribe Mounjaro directly?
No. Mounjaro prescription is restricted to specialist tier 3 weight management services in the UK. Your GP can refer you and discuss eligibility, but the specialist team makes the prescribing decision. GPs cannot initiate Mounjaro treatment outside specialist services.
What health conditions count towards NHS Mounjaro eligibility?
Type 2 diabetes, prediabetes, high blood pressure, obstructive sleep apnoea, abnormal blood fats, and a history of heart attack or stroke. Even one of these conditions, alongside a BMI of 27–29.9, can make you eligible. Your GP or specialist will assess which apply to you.
Is Mounjaro the same as Wegovy on the NHS?
No. Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist. Wegovy (semaglutide) is a GLP-1-only agonist. Both are NHS-approved for weight management but through the same specialist tier 3 pathway. Your specialist team will decide which is most suitable based on your health profile.
Can I switch from private Mounjaro to NHS Mounjaro?
Possibly, but it depends on your local NHS service. Once you've been assessed by the NHS specialist team and deemed eligible, they can prescribe NHS Mounjaro. However, there's usually no automatic transition—you'd need to go through the NHS referral pathway. Discuss this with your GP if you're considering a switch.
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.