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 Long Has Mounjaro Been Around in the UK?
Mounjaro (tirzepatide) was first approved for weight management in the UK in 2023, making it one of the newer prescription weight loss options available to adults. Developed by Eli Lilly and manufactured as a convenient once-weekly KwikPen injection, Mounjaro became available relatively recently compared to some other weight loss medications. If you're considering this medication, understanding its availability and cost in the UK is essential. Our free BMI calculator can help you check if you meet the typical eligibility criteria, and our GLP-1 weight loss calculator can show you projected outcomes based on clinical trial data.
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.
Mounjaro Cost & Access in the UK: NHS vs Private
Mounjaro became available on the NHS in 2023 through specialist weight management services, though regional availability varies significantly. NHS access requires referral from your GP to a tier 3 or tier 4 specialist weight management service, and waiting lists in many areas can extend from several months to over a year. Private prescription is available through online consultations with UK-licensed prescribers, typically costing between £129 and £320 per month depending on your dose. The cost reflects the tirzepatide dose you're prescribed—higher doses like 15mg cost more than starting doses of 2.5mg. Private access bypasses NHS waiting lists entirely and doesn't require a GP referral, though you'll need to meet clinical eligibility criteria and pass an online assessment. Both routes require a valid prescription before dispensing, and individual costs may vary by provider and whether you qualify for any payment plans.
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.
Understanding Mounjaro Eligibility and What to Expect
You may be eligible for Mounjaro if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, prediabetes, or cardiovascular disease. Lower thresholds apply if you're from South Asian, Chinese, Black African, or Black Caribbean backgrounds—often starting at BMI 27.5 or above. An online consultation assesses your medical history, current medications, and suitability before a prescription is issued. The process typically takes 24–48 hours. You'll receive your KwikPen injections by post, with clear storage instructions (refrigerate at 2–8°C unopened, or at room temperature for up to 30 days after first use). Starting doses begin at 2.5mg, increasing weekly over several weeks, with the maximum dose reaching 15mg. Individual results vary—clinical trials showed average weight loss of 15–21% of body weight alongside diet and exercise changes.
- 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.
When was Mounjaro first approved for weight loss in the UK?
Mounjaro (tirzepatide) received UK approval for weight management in 2023. It became available through both NHS specialist services and private online prescribing, making it one of the newer GLP-1 and GIP receptor agonist options available to UK adults seeking prescription weight loss support.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129 to £320 per month, depending on your dose. Starting doses (2.5mg) cost less than maintenance doses (15mg). Some providers offer payment plans. Always check with your prescriber about exact pricing, as costs may vary between different online services.
Can I get Mounjaro on the NHS?
Yes, Mounjaro is available on the NHS through specialist tier 3 and tier 4 weight management services. However, you need a GP referral and may face significant waiting lists in your area. NHS access varies by region—some areas have shorter waits than others. Private prescription is an alternative if you don't want to wait.
How is Mounjaro different from Wegovy in terms of availability?
Both Mounjaro and Wegovy are prescription-only and available privately in the UK. Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is a GLP-1 agonist only. Mounjaro typically shows slightly higher average weight loss in clinical trials, but both require clinical assessment. Availability through NHS specialist services applies to both, though regional variation exists.
What happens after my online consultation for Mounjaro?
If approved following your online assessment, a UK-licensed prescriber issues a prescription. Your Mounjaro KwikPens are then dispensed by a GPhC-registered pharmacy and posted to you, usually within 2–5 working days. You'll receive clear instructions on storage, injection technique, and dose titration (increasing gradually over weeks).
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.