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
When Should You Increase Your Mounjaro Dose?
If you're taking Mounjaro (tirzepatide), your prescriber will follow a structured dose escalation plan. Your dose typically increases every 4 weeks based on how you're tolerating the current dose and your weight loss progress. This guide explains the UK Mounjaro dosing schedule, how dose titration works, and what to expect when moving to a higher dose. Always follow your prescriber's guidance—they will assess your individual response and determine the right timing for dose increases. Use our free GLP-1 weight loss calculator to explore potential outcomes at different Mounjaro 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.
Mounjaro Dose Titration Schedule and Timeline
Mounjaro follows a standard 4-week escalation schedule in the UK, with each dose held for a minimum of 4 weeks before increasing. This allows your body to adjust and helps your prescriber monitor your tolerance and weight loss response.
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg (first maintenance dose)
- Weeks 9–12: 7.5 mg (escalation)
- Weeks 13–16: 10 mg (escalation)
- Weeks 17–20: 12.5 mg (escalation)
- Week 21 onwards: 15 mg (maximum dose)
Your prescriber may adjust this timeline based on side effects, tolerability, or weight loss response. Some patients stay at 5 mg or 10 mg for longer if they are experiencing good results or managing side effects well. Dose increases are never rushed—your prescriber prioritises safety and sustainable weight loss over speed.
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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.
When Your Prescriber May Delay or Skip Dose Increases
Not everyone escalates to the maximum 15 mg dose, and your prescriber may pause or skip dose increases if:
- You are experiencing persistent or severe side effects (nausea, vomiting, diarrhoea)
- Your weight loss is already satisfactory at your current dose
- You have underlying health conditions that warrant a more cautious approach
- Your tolerability to the current dose is still being assessed
Mounjaro eligibility and dosing are individualised. Your prescriber will balance weight loss effectiveness against side effect burden and your overall health. Some patients find their optimal dose at 5 mg or 10 mg and maintain excellent results without escalating further. Track your progress using our free progress tracker to share measurable outcomes with your prescriber at each review.
- 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 ask my GP to increase my Mounjaro dose early?
No, dose increases should follow the 4-week minimum schedule set by your prescriber. Early escalation increases side effect risk without additional benefit. Contact your prescriber if you have concerns about your progress or tolerability—they may advise staying at your current dose longer or adjusting your lifestyle approach.
What happens if I have bad side effects when I go up a dose on Mounjaro?
Side effects are common, especially when increasing doses. Most ease within 1–2 weeks as your body adjusts. If side effects are severe or persistent, contact your prescriber immediately. They may recommend staying at your current dose longer, using management strategies, or pausing escalation.
How do I know if my Mounjaro dose is working?
Your prescriber will assess weight loss progress, appetite changes, and overall tolerability at each review. Clinical trials showed average weight loss of 15–21% with tirzepatide, but individual results vary. Use our GLP-1 weight loss calculator to estimate potential outcomes and track your progress over time.
Will I definitely reach the 15 mg dose on Mounjaro?
No. Many patients achieve their weight loss goals at lower doses (5 mg, 10 mg, or 12.5 mg). Your prescriber will determine your optimal dose based on efficacy and tolerability. Some patients stay below 15 mg indefinitely if results are good and side effects are manageable.
What's the difference between Mounjaro and Wegovy dose schedules?
Mounjaro (tirzepatide) escalates from 2.5 mg to 15 mg over 20+ weeks; Wegovy (semaglutide) escalates from 0.25 mg to 2.4 mg over 16+ weeks. Mounjaro is a dual GIP + GLP-1 agonist; Wegovy is GLP-1 only. Both are UK prescription-only, and dose timing depends on individual tolerance and clinical assessment.
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.