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
Can You Get Mounjaro Free On The NHS?
Yes, Mounjaro (tirzepatide) is available free on the NHS for eligible adults, but access is limited and varies significantly by region. Unlike some medications, Mounjaro prescriptions are not issued by your GP in primary care — they come through specialist tier 3 weight management services. NICE has approved tirzepatide for use within the NHS, but availability depends on your local Integrated Care Board (ICB) and whether your local service has funding and capacity. Waiting times can be substantial in many areas. Our GLP-1 weight loss calculator can help you explore potential outcomes if you do qualify.
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 Access: Eligibility And The Tier 3 Pathway
NICE approval: In 2023, the National Institute for Health and Care Excellence (NICE) recommended tirzepatide for use within NHS specialist weight management services. However, NICE approval does not assures immediate access across all trusts — funding and implementation vary by region.
Who is eligible: You may qualify for NHS Mounjaro if you have 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, hypertension, dyslipidaemia, sleep apnoea, or cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply (BMI 27.5+).
The tier 3 route: You cannot simply ask your GP for a Mounjaro KwikPen prescription. Access is through NHS tier 3 specialist weight management services. Your GP must refer you to the local service, where a multidisciplinary team (doctors, dietitians, psychologists) assesses your suitability. If approved, they manage your tirzepatide dose titration and monitoring throughout your treatment.
Regional variation: Some ICBs have funded Mounjaro; others have not. Some services have waiting lists of months or years; others are not yet prescribing it. Contact your local weight management service or ask your GP about current availability in your area.
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: What You Should Know
NHS advantages: Free medication, specialist clinical oversight, integrated mental health and dietitian support, monitoring of blood pressure and metabolic markers, no out-of-pocket costs.
NHS disadvantages: Potentially long waiting lists (sometimes 6–18 months), limited regional availability, tier 3 services may have strict eligibility criteria or additional requirements, appointment gaps between dose increases.
Private route: If you do not wish to wait or your local NHS service has not commissioned Mounjaro, you can access tirzepatide privately through a UK-licensed prescriber following an online clinical assessment. Private prescriptions cost approximately £200–£350 per month depending on dose and provider, but there are no waiting lists. You pay for medication and consultations directly.
Mixed approach: Some people start privately while waiting for NHS access, then transition to NHS prescribing once approved by the specialist service. Always inform both your GP and any private prescriber about your parallel NHS referral.
- 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 do I access Mounjaro on the NHS?
Ask your GP to refer you to your local NHS tier 3 weight management service. They will assess your eligibility based on BMI and health conditions, then decide whether to prescribe tirzepatide as part of a structured programme. Specialist nurses or doctors manage your dose titration and ongoing care.
What is the difference between tier 3 and tier 4 services?
Tier 3 services are specialist multidisciplinary weight management clinics offering medication, behaviour change support, and medical monitoring. Tier 4 is bariatric (weight loss) surgery, only considered for severe obesity with significant comorbidities after tier 3 interventions have been tried.
How long are NHS waiting lists for Mounjaro?
Waiting times vary dramatically by region — from a few weeks in well-resourced areas to 12–18+ months in others. Some ICBs have not yet commissioned tirzepatide at all. Contact your local NHS weight management service directly for current waiting times.
Can I get Mounjaro free if my BMI is 27–29?
Yes, if you have a weight-related health condition such as type 2 diabetes, hypertension, dyslipidaemia, sleep apnoea, or cardiovascular disease. Your tier 3 team will assess your individual circumstances. South Asian and certain other ethnic groups may have lower thresholds.
Is Mounjaro or Wegovy more available on the NHS?
Both tirzepatide and semaglutide are NICE-approved, but availability varies by trust. Wegovy may be slightly more available in some areas due to earlier rollout, but this is not consistent. Ask your GP which medication your local service currently offers or prefers based on current commissioning.
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.