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
How Do I Get Mounjaro on NHS?
Getting Mounjaro on the NHS involves referral to specialist weight management services, which is different from standard GP prescription. Eligibility depends on your BMI, weight-related health conditions, and local NHS availability. NHS access to tirzepatide is now available through NICE-approved specialist services, but the process, waiting times, and availability vary significantly across different regions in the UK. Here's how to navigate the NHS pathway.
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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 Pathway for Mounjaro Access
The NHS prescribes Mounjaro (tirzepatide) through specialist weight management services, typically known as tier 3 or tier 4 services. You cannot obtain Mounjaro as a standard GP prescription. Instead, you must be referred by your GP to a specialist multidisciplinary weight management team, usually based at hospital trusts or specialist NHS weight management centres.
- Step 1: Speak to your GP. Request a referral to your local NHS specialist weight management service. Your GP will assess your eligibility based on BMI and health conditions.
- Step 2: Be assessed by the specialist team. The NHS team will conduct a full health assessment, review your medical history, and discuss whether tirzepatide is appropriate for you.
- Step 3: If approved, you'll receive a prescription and guidance on self-administration of the Mounjaro KwikPen. The specialist team will manage your dose titration and monitor your progress.
NICE (National Institute for Health and Care Excellence) approved tirzepatide for use in NHS specialist weight management services, making it now available on the NHS — though access remains patchy and waiting lists can be lengthy in many regions.
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.
Eligibility for NHS Mounjaro
You may be eligible for NHS Mounjaro if you have:
- BMI of 30 kg/m² or above, or BMI 27–29.9 with at least one weight-related health condition
- For South Asian, Chinese, Black African, or Black Caribbean adults: lower thresholds may apply (BMI 27.5 or above)
- Weight-related conditions such as: type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or previous cardiovascular disease
You cannot access NHS Mounjaro if you are under 18, pregnant, breastfeeding, or allergic to tirzepatide. Use our free BMI calculator to check your personal BMI and understand where you stand relative to NHS eligibility thresholds.
- 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 is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region. Some NHS areas have waiting lists of several months to over a year. Contact your local specialist weight management service for an estimate specific to your area. In the meantime, your GP can support you with diet and exercise advice.
What's the difference between getting Mounjaro on NHS vs privately?
NHS Mounjaro is free (on prescription) but requires referral to specialist services and involves waiting lists. Private access is faster (usually 1–2 weeks) but costs around £129–£320 per month depending on dose. Both require a clinical assessment from a licensed prescriber.
Can my GP prescribe Mounjaro directly?
No. Mounjaro is only prescribed through NHS specialist weight management services (tier 3 or tier 4), not by standard GP prescription. Your GP can refer you, but cannot prescribe it directly unless you're already under a specialist team's care.
Will Mounjaro help me lose weight faster than diet and exercise alone?
Clinical trials showed Mounjaro helped participants lose an average of 15–21% of body weight alongside diet and exercise changes. Individual results vary significantly. Mounjaro works best when combined with a reduced-calorie diet and increased physical activity, not as a substitute.
How does Mounjaro's dose titration work on the NHS?
You start at 2.5 mg once weekly and increase by 2.5 mg every 4 weeks until you reach an effective maintenance dose (usually 10–15 mg). Your specialist team will monitor your progress and side effects, adjusting the dose based on your response and tolerability.
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.