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?
Mounjaro (tirzepatide) is a prescription-only weight management injection given as a once-weekly dose that starts low and increases gradually over time. Your prescriber will advise you on when to increase your Mounjaro dose based on your individual response, tolerance, and any side effects you experience. This guide explains the standard UK dose escalation schedule, what determines timing, and how to discuss dose increases with your healthcare provider. Use our free GLP-1 weight loss calculator to understand 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.
Standard Mounjaro Dose Escalation Schedule
Mounjaro follows a structured dose titration schedule designed to help your body adjust gradually. You start at 2.5 mg once weekly for the first 4 weeks, then increase to 5 mg for weeks 5–8. From week 9 onwards, your dose can be escalated in increments of 2.5 mg (to 7.5 mg, then 10 mg, then 12.5 mg) every 4 weeks if needed, up to a maximum of 15 mg once weekly.
Each dose increase happens at least 4 weeks apart — this allows your prescriber to assess your response and side effects before moving to the next level. Most people achieve good weight loss results at 10 mg or 15 mg, though individual responses vary significantly. Your prescriber will not automatically increase your dose; they will discuss whether escalation is appropriate for you based on your progress, side effects, and goals.
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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.
Factors That Determine Dose Increase Timing
Your prescriber considers several factors before recommending a dose increase. These include weight loss progress — if you are losing weight at a satisfactory rate, escalation may continue. Side effects play a major role; if you are experiencing significant nausea, vomiting, or other adverse effects, your prescriber may delay or skip a dose increase to allow adjustment. Appetite suppression and how satisfied you feel after meals also inform the decision. If a lower dose is already giving you good appetite control and sustainable weight loss, a higher dose may not be necessary. Always discuss any concerns or side effects with your prescriber before your next scheduled dose increase.
- 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.
What if I am not losing weight on my current Mounjaro dose?
Contact your prescriber. They may increase your dose, but they will also review your diet and activity levels. Weight loss depends on creating a calorie deficit through both reduced intake and increased movement. Your prescriber may suggest dietary assessment or lifestyle changes before escalating. If you have been on the same dose for 8+ weeks with minimal loss, dose increase discussion is reasonable.
Can I skip a dose increase if I prefer to stay at a lower dose?
Yes. Dose escalation is not mandatory. If you are achieving good results and managing side effects well at your current dose, you and your prescriber can agree to remain there. There is no clinical requirement to reach the maximum 15 mg dose. Your goals and comfort matter more than reaching a specific dose level.
How long does it take to reach the maximum 15 mg Mounjaro dose?
Following the standard 4-week escalation schedule, it takes approximately 20–24 weeks (5–6 months) to progress from 2.5 mg to 15 mg. This assumes no delays due to side effects or pauses in escalation. In practice, many people stabilise at lower doses (5 mg or 10 mg) and do not progress further.
What happens if I experience severe side effects during a dose increase?
Inform your prescriber immediately. They may delay your next scheduled increase, stay at your current dose longer, or reduce back to your previous dose if necessary. Side effects like severe nausea or vomiting are your prescriber's priority. Do not stop your injection without guidance; discuss options with them first.
Does Mounjaro work better at higher doses than lower doses?
Clinical trials showed that higher doses of tirzepatide produce slightly greater average weight loss — 15 mg achieved ~clinically studied weight loss versus ~15% at 5 mg. However, individual variation is significant, and many people achieve satisfactory results at 5 mg or 10 mg. Your prescriber will recommend a dose appropriate for your response and tolerance, not necessarily the 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.