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
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What Is the Highest Mounjaro Dose in the UK?
The highest Mounjaro dose available in the UK is 15 mg, administered as a once-weekly injection. Most people reach this maximum dose after a gradual dose titration process lasting 20 weeks or more. Mounjaro (tirzepatide) is a prescription-only weight management injection licensed in the UK. Access is available through both NHS specialist services and private online prescribing, though costs and waiting times differ significantly between the two routes. This guide explains the maximum dose, how to access it, and what you can expect to pay.
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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.
Maximum Mounjaro Dose and Titration Schedule
The maximum Mounjaro dose is 15 mg per week, delivered as a single injection using a pre-filled KwikPen device. Most patients do not start at this dose. Instead, Mounjaro uses a gradual dose titration schedule to reduce side effects and allow the body to adjust:
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg
- Weeks 9–12: 7.5 mg
- Weeks 13–16: 10 mg
- Weeks 17–20: 12.5 mg
- Week 21+: 15 mg (maximum maintenance)
Each dose must be used for a minimum of 4 weeks before increasing. Not everyone reaches 15 mg — many people achieve their weight loss goals at lower doses (5 mg, 10 mg, or 12.5 mg) and may stay at that dose long-term. Your prescriber will assess your individual response and adjust accordingly. The 15 mg dose is the ceiling; there is no higher dose approved in the UK.
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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.
Accessing Mounjaro in the UK: NHS vs Private Cost
In the UK, Mounjaro is available through two main routes:
- NHS route: Referral to tier 3 specialist weight management services. Cost is covered by the NHS, but waiting times can be several months to years depending on your region. NICE has approved tirzepatide for NHS use, though availability varies by Integrated Care Board (ICB).
- Private route: Online consultation with a UK-licensed prescriber, followed by a prescription dispensed by a GPhC-registered pharmacy. Costs range from approximately £129–£320 per month depending on the dose. Private prescriptions are available without an NHS referral, though a clinical assessment is still required. Many people choose private access due to shorter waiting times.
Our GLP-1 weight loss calculator can help you estimate potential outcomes and explore options before speaking to a prescriber.
- 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 much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose. Lower doses (2.5 mg to 5 mg) cost less; higher doses (10 mg to 15 mg) cost more. Each KwikPen contains 4 weekly injections. Prices vary between GPhC-registered pharmacies, so it's worth comparing. Some private providers offer subscription discounts or bundle pricing.
Can I get Mounjaro on the NHS in the UK?
Yes. NICE has approved tirzepatide (Mounjaro) for NHS use within specialist tier 3 weight management services. You'll need a GP referral to access these services. NHS provision is free, but availability and waiting times vary significantly by region. Some areas have waiting lists of many months. Ask your GP about local specialist services in your area.
What happens if I don't reach the 15 mg dose?
Many people achieve their weight loss goals at doses lower than 15 mg (often 5 mg, 10 mg, or 12.5 mg). There is no requirement to reach the maximum dose. Your prescriber will work with you to find the lowest effective dose that minimises side effects whilst supporting your weight management goals. You can remain on a lower dose long-term if it's working for you.
How long does Mounjaro dose titration take?
Full dose titration to 15 mg typically takes 20 weeks (about 5 months) if you increase every 4 weeks. However, some people may increase more slowly or pause at a lower dose if they're experiencing significant side effects or have achieved their goals. Your prescriber will personalise the schedule based on your response and tolerability.
Is Mounjaro the same as Wegovy?
No. Both are GLP-1 weight loss injections licensed in the UK, but Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, whilst Wegovy (semaglutide) is a GLP-1-only agonist. Mounjaro's maximum dose is 15 mg per week; Wegovy's is 2.4 mg per week. Clinical trials show both can support weight loss, though individual results vary. Your prescriber will advise which is suitable for you.
Ready to take control of your weight loss journey?
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