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
What Is the Maximum Mounjaro Dose in the UK?
The maximum Mounjaro dose available in the UK is 15 mg, taken as a once-weekly injection. However, not all patients require or reach this dose—most achieve effective weight management at lower doses like 5 mg, 10 mg, or 12.5 mg. Your prescriber will start you on a lower dose and gradually increase it based on your response and tolerance. The dose titration process typically takes 5 to 6 months to reach a maintenance dose. Always follow your prescriber's guidance, as the right dose varies between individuals depending on health conditions, other medications, and weight loss goals. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses.
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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.
How Mounjaro Dose Titration Works in the UK
Mounjaro dosing follows a structured titration schedule that allows your body to adjust and helps minimise side effects. You start at 2.5 mg weekly for the first 4 weeks, then increase by increments every 4 weeks: 5 mg (weeks 5–8), 7.5 mg (weeks 9–12), 10 mg (weeks 13–16), 12.5 mg (weeks 17–20), and finally 15 mg (week 21 onwards). This gradual escalation means reaching maximum dose takes approximately 20 weeks, or about 5 months. Your NHS specialist or private prescriber may pause increases if you experience significant side effects, or may extend the timeline based on your response. Each dose comes as a pre-filled KwikPen containing 4 weekly injections. The dose you eventually settle on—which may be anywhere from 5 mg to 15 mg—is your maintenance dose. Most patients find their effective dose before reaching 15 mg. Clinical trials show that meaningful weight loss occurs across the dose range, and higher doses do not assures proportionally greater results for everyone.
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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.
NHS vs Private Access for Maximum Mounjaro Doses
In the UK, access to Mounjaro at any dose requires a prescription from a licensed healthcare professional. NHS specialist services (tier 3 weight management) can prescribe Mounjaro, but availability is limited and waiting lists are often lengthy—some regions have waits of 12 months or more. Private online prescribing services offer faster access to the full dose range and may be more accessible if your local NHS service has restrictions. Both routes require a clinical assessment and ongoing monitoring. Whether through NHS or private prescribing, your prescriber will determine the appropriate starting dose and titration schedule for you. The maximum dose available remains 15 mg regardless of route. Use our free BMI calculator to understand your baseline health metrics before speaking with a prescriber about your eligibility and treatment options.
- 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.
Can I start Mounjaro at the maximum 15 mg dose?
No. Mounjaro always begins at 2.5 mg and increases gradually over weeks. Starting at 15 mg would cause severe side effects and is not medically appropriate. The 4-week titration intervals allow your body to adapt, reducing nausea and gastrointestinal symptoms.
What is the typical maintenance dose for Mounjaro in the UK?
Many patients stabilise between 5 mg and 10 mg. The "right" dose varies by individual—some see excellent results at 7.5 mg, others need 12.5 mg or 15 mg. Your prescriber adjusts based on weight loss response and side effect tolerance.
Does Mounjaro work better at 15 mg than at 10 mg?
Clinical data shows diminishing returns at higher doses. SURMOUNT trials found average weight loss of approximately 20.9% at 15 mg versus 19.5% at 10 mg—a modest difference. Individual response varies; some achieve their goal at lower doses.
How long does it take to reach maximum Mounjaro dose?
The standard titration schedule takes approximately 20 weeks (5 months) to progress from 2.5 mg to 15 mg, with 4-week intervals between increases. Your prescriber may extend this timeline if you experience side effects.
What if I cannot tolerate Mounjaro at higher doses?
Your prescriber will pause titration and keep you at a dose you tolerate well. Effective weight loss is achievable at 5 mg, 7.5 mg, or 10 mg—you do not need to reach 15 mg. Comfort and adherence matter more than maximum dose.
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.