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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NICE Tirzepatide — How to Access in the UK
NICE (the National Institute for Health and Care Excellence) has approved tirzepatide for weight management in UK adults through specialist NHS services. This approval means eligible patients can now access Mounjaro (the brand name for tirzepatide) as a prescription-only medicine, either through the NHS or privately. Understanding your options — NHS availability, private prescription costs, and eligibility criteria — helps you decide the best route for your situation. This guide explains NICE tirzepatide approval, how it works in practice, and what to expect when accessing this GLP-1 and GIP receptor agonist medication in the UK.
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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.
How NICE Approval Works & Private Access Costs
NICE approval means tirzepatide is now an approved weight management option for UK adults meeting specific criteria. However, approval does not assures automatic NHS access — availability depends on your local Integrated Care Board (ICB) and specialist weight management service capacity.
- NHS route: Referral from your GP to a tier 3 specialist weight management service. NICE-approved, but limited availability and potentially lengthy waiting lists in many regions.
- Private prescription route: Online consultation with a UK-licensed prescriber followed by dispensing via a GPhC-registered pharmacy. Available without NHS referral. Private costs typically range from £150–£300 per month depending on dose, with starting dose (2.5 mg) at the lower end and maximum dose (15 mg) at the higher end.
- Eligibility: BMI 30 or above, or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease, sleep apnoea). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds (27.5+).
A weekly weight loss injection like tirzepatide works by activating GIP and GLP-1 receptor pathways, helping regulate appetite and support sustainable weight management alongside diet and physical activity.
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: Timelines, Costs & How to Access
NHS access is free but involves GP referral, specialist assessment, and can have waiting times of several months to over a year depending on your region. Private access is faster — typically 3–7 days from online consultation to first injection — but requires payment. Using our free GLP-1 weight loss calculator can help you estimate potential outcomes at different doses before making your decision.
To access privately: Complete an online health questionnaire with a UK-licensed prescriber, receive a prescription if approved, and have medication dispensed by a GPhC-registered pharmacy. To access via NHS: Ask your GP for a referral to your local tier 3 weight management service, attend assessment, and await availability. Both routes require clinical assessment to confirm tirzepatide is suitable for you.
- 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.
Is NICE tirzepatide available on the NHS everywhere in the UK?
NICE approval means tirzepatide is an approved NHS option, but availability varies by region. Not all ICBs have funded specialist weight management services offering tirzepatide yet. Ask your GP whether your local service offers it, or contact your ICB directly. Waiting lists are often long where available.
How much does tirzepatide cost privately in the UK?
Private tirzepatide costs typically range from £150–£300 per month depending on dose. Starting dose (2.5 mg) costs less; maximum dose (15 mg) costs more. Prices vary between private prescribers and pharmacies. Always confirm the total cost including consultation and medication before starting.
What is the difference between tirzepatide and semaglutide (Wegovy)?
Tirzepatide (Mounjaro) activates both GIP and GLP-1 receptors (dual mechanism), while semaglutide (Wegovy) activates GLP-1 only. Clinical trials suggest tirzepatide may produce slightly greater average weight loss, but individual results vary significantly. Both are prescription-only and require clinical assessment.
Do I need a GP referral to access tirzepatide privately?
No. Private prescriptions bypass the NHS referral process. You complete an online consultation directly with a UK-licensed prescriber, and if approved, receive a prescription dispensed by a GPhC-registered pharmacy. However, you should inform your GP you're taking any prescription medication.
What does NICE tirzepatide approval mean for weight management?
NICE approval confirms tirzepatide is clinically effective and cost-effective for eligible UK adults. It means the NHS can fund it, and private providers can legally prescribe it. Approval is based on clinical trial evidence showing modest but meaningful weight loss alongside lifestyle changes.
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.