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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Mounjaro Dosage Chart: Complete UK Guide
Mounjaro (tirzepatide) is prescribed at increasing doses over several months, starting at 2.5mg and escalating up to a maximum of 15mg once weekly. This step-by-step dosage chart explains the UK titration schedule, what happens at each dose level, and how long you stay on each before potentially increasing. Understanding your dosage progression helps you know what to expect as your treatment develops.
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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.
Mounjaro Dose Titration Schedule
Mounjaro dosing follows a step-wise escalation protocol designed to help your body adjust gradually and minimise side effects. You start at the lowest dose and typically increase every 4 weeks if clinically appropriate.
- Weeks 1–4: 2.5mg once weekly (starting/adjustment dose)
- Weeks 5–8: 5mg once weekly (first maintenance level)
- Weeks 9–12: 7.5mg once weekly (escalation if needed)
- Weeks 13–16: 10mg once weekly (continued escalation)
- Weeks 17–20: 12.5mg once weekly (higher maintenance)
- Week 21+: 15mg once weekly (maximum licensed dose)
Each KwikPen contains exactly 4 doses — one month's supply at your current dose. You may not escalate to the next dose if side effects are troublesome; your prescriber can adjust timing based on your individual tolerance. Not everyone reaches the maximum 15mg dose; many people achieve their weight management goals at 10mg or 12.5mg.
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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.
Expected Weight Loss at Different Mounjaro Doses
Clinical trial data (SURMOUNT-1) shows average weight loss varies by dose level. At 5mg, participants lost approximately 15% of body weight; at 10mg, around 19.5%; and at 15mg, approximately 20.9% — though individual results vary significantly. These results were achieved alongside a reduced-calorie diet and increased physical activity over 72 weeks. Your personal outcome depends on many factors including your starting weight, metabolism, lifestyle adherence, and individual response to the medication. Use our free GLP-1 weight loss calculator to see projected results at different doses.
- 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 skip doses or adjust the Mounjaro titration schedule myself?
No. Your prescriber will manage your dose escalation based on your tolerance, side effects, and response. Never skip doses or self-escalate. If you experience bothersome side effects, contact your prescriber — they may slow your escalation or adjust timing rather than stopping treatment.
What if I miss a Mounjaro injection?
If missed within 4 days, take it as soon as you remember and resume your normal weekly schedule. If more than 4 days have passed, skip that dose and take your next dose on the scheduled day. Never take a double dose. Minimum time between doses is 72 hours (3 days).
Do I stay on 15mg Mounjaro forever, or can I reduce doses?
This depends on your prescriber's guidance and your weight management goals. Some people maintain long-term on higher doses; others may eventually reduce to a maintenance dose. Weight regain can occur if treatment is stopped, so any dose changes should be discussed with your prescriber.
Why does Mounjaro increase so slowly — can't I go straight to 15mg?
Slow titration (4-week intervals) helps your body adapt and reduces severe side effects like nausea. Rapid escalation dramatically increases nausea, vomiting, and other GI effects, making the medication difficult to tolerate. The gradual approach improves long-term adherence and safety.
How is Mounjaro different from Wegovy dosing?
Mounjaro (tirzepatide) starts at 2.5mg and escalates to 15mg. Wegovy (semaglutide) starts at 0.25mg and escalates to 2.4mg. Both are once-weekly injections, but they have different starting and maximum doses because they're different medications with different potencies. Your prescriber chooses the most appropriate option for you.
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.