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
Understanding Mounjaro Check-Ups in the UK NHS
If you're considering Mounjaro (tirzepatide) for weight management in the UK, understanding the NHS check-up and assessment process is essential. Mounjaro is a prescription-only, once-weekly injectable that has been approved by NICE for use within NHS specialist weight management services. This guide explains how the NHS assessment works, eligibility criteria, and what to expect during your consultation with a healthcare professional.
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 Eligibility and Assessment for Mounjaro
The NHS prescribes Mounjaro through tier 3 specialist weight management services, not through standard GP prescriptions. You'll typically need a GP referral to access these services. Eligibility criteria include:
- BMI of 30 kg/m² or above, or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease history)
- For South Asian, Chinese, Black African, or Black Caribbean adults: lower BMI thresholds may apply (starting from 27.5 or above)
- Age 18 or over
- Not pregnant or breastfeeding
- No contraindications such as personal or family history of medullary thyroid carcinoma
During your NHS check-up, the specialist team will assess your weight, BMI, health history, and whether Mounjaro dose titration is appropriate for you. The Mounjaro KwikPen delivers doses from 2.5 mg up to 15 mg weekly, with typically four weeks at each dose level before escalation. NHS assessment also includes baseline screening for contraindications and suitability for this medication.
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 Availability and the Private Alternative
NHS access to Mounjaro varies significantly by region — some areas have specialist services with availability, while others have lengthy waiting lists. NICE has approved tirzepatide (Mounjaro) for NHS use, but regional ICBs (Integrated Care Boards) control commissioning decisions and funding. Many patients experience waits of several months to over a year for NHS tier 3 assessment.
Private route: Mounjaro is also available through GPhC-registered online pharmacies following a private clinical assessment with a UK-licensed prescriber. This route does not require NHS referral and typically offers faster access. Compare using our free GLP-1 weight loss calculator to project potential outcomes and understand what to expect with different doses. Both routes require a proper prescription and clinical assessment — Mounjaro is never available without professional medical review.
When considering your options, use our free BMI calculator to confirm your current BMI category and understand your starting point. Check your weight converter to ensure you're tracking your measurements consistently between kg, stone, and pounds — this helps during clinical assessments. If you proceed with treatment, our free progress tracker lets you log your weight loss journey week by week, which is valuable information to share with your healthcare team at check-ups.
- 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 an NHS Mounjaro assessment take?
Initial NHS assessment through a tier 3 weight management service typically takes 1–2 hours, including blood tests, weight/BMI measurement, medical history review, and discussion of treatment options. Follow-up appointments to monitor progress and assess dose escalation usually take 20–30 minutes.
Will I need blood tests before starting Mounjaro on the NHS?
Yes. NHS assessment includes baseline blood tests to check kidney function, liver function, and fasting glucose levels. These help ensure Mounjaro is safe for you. Blood tests may be repeated at intervals during treatment to monitor your response and health.
What's the difference between Mounjaro vs Wegovy through the NHS?
Both are GLP-1 (or dual GIP/GLP-1) receptor agonists approved by NICE for NHS use. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Both require NHS tier 3 referral and assessment. Clinical trials showed different average weight loss outcomes — Mounjaro approximately 15–21% body weight, Wegovy approximately 15% — though individual results vary significantly.
Can my GP prescribe Mounjaro directly, or must I see a specialist?
Mounjaro is prescribed through NHS tier 3 specialist weight management services following referral from your GP. Your GP cannot prescribe it directly from the surgery. You'll need your GP to refer you to your local specialist service first, then the specialist team assesses your suitability and manages ongoing prescribing and monitoring.
How often will I have check-ups while taking Mounjaro on the NHS?
Typically, you'll have an initial assessment, then follow-up appointments every 4–8 weeks during the dose escalation phase (first 5–6 months), then every 3–6 months once on a maintenance dose. Appointments monitor your weight loss progress, any side effects, and whether dose increases are needed. Your care plan may vary depending on your NHS service and individual needs.
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.