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
Is There a Generic Version of Mounjaro Available in the UK?
Mounjaro (tirzepatide) is currently only available as the brand name medication in the UK — there is no generic version yet. Tirzepatide was approved by the MHRA in 2023, and pharmaceutical patents protect it until at least 2034. This means the brand name Mounjaro KwikPen remains the only licensed formulation available through NHS specialist services or private prescribing. Understanding availability and cost options can help you explore whether prescription weight management is right for you.
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.
When Will Mounjaro Generic Become Available?
Mounjaro's patent protection in the UK extends until approximately 2034, meaning a generic tirzepatide version is unlikely to become available for several years. Once patents expire, generic manufacturers can apply to produce tirzepatide at lower cost, similar to how generic versions of older GLP-1 medications eventually emerged. The timeline depends on MHRA approval processes and potential patent challenges. Until then, you'll access tirzepatide only through the brand name Mounjaro KwikPen. Your prescriber can assess your eligibility for treatment regardless of generic availability — what matters is whether the medication is clinically appropriate for your situation, which our free GLP-1 weight loss calculator can help you explore.
- Patent expiry in UK: approximately 2034
- Generic versions unlikely before patent expiry
- Current cost reflects brand name pricing
- Effectiveness remains the same regardless of patent status
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.
Current Access Routes for Mounjaro in the UK
Right now, Mounjaro is available through two main routes: NHS specialist tier 3 weight management services (with significant regional variation in availability and waiting times) or private online prescribing services following a clinical assessment. NHS access requires referral from your GP, though availability varies dramatically across different integrated care boards. Private access through UK-licensed prescribers offers faster availability but involves direct costs. Regardless of access route, you'll receive the genuine Mounjaro KwikPen product. Your GP can discuss which option suits your circumstances, and our BMI calculator above can help determine whether you meet typical eligibility criteria (BMI 30 or above, or 27 or above with weight-related health conditions).
- 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.
Why is there no generic Mounjaro in the UK yet?
Tirzepatide patents protect Mounjaro until around 2034. Generic versions can only be manufactured after patent expiry. This is standard pharmaceutical practice and helps manufacturers recoup development costs. Once patents expire, generic versions will likely become available at lower cost.
Will generic Mounjaro be cheaper than brand name?
Yes, generic tirzepatide will typically be significantly cheaper than brand name Mounjaro once it becomes available. Generic medications usually cost 30–80% less than brand names. However, the actual cost reduction will depend on NHS pricing negotiations and private provider competition at that time.
Is brand name Mounjaro the same as generic tirzepatide will be?
Yes, absolutely. Generic tirzepatide will contain the same active ingredient at the same dose, meeting identical quality standards. The only differences will be cost and possibly the brand name on the box — effectiveness and safety will be identical to Mounjaro KwikPen.
Can I access Mounjaro on the NHS now, or do I need to wait for generic?
You can access Mounjaro on the NHS now through specialist weight management services, though availability and waiting times vary by region. You don't need to wait for generic versions — your GP can refer you to tier 3 services to explore eligibility and access today.
What's the difference between Mounjaro and other weight loss injections?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whereas Wegovy (semaglutide) is a single GLP-1 agonist. Clinical trials showed Mounjaro achieved slightly higher average weight loss than Wegovy — approximately 20.9% versus 14.9% body weight — though individual results vary significantly.
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.