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
How Mounjaro Dose Increases Work
Mounjaro (tirzepatide) is a prescription-only weight management injection that works through a gradual dose increase schedule called titration. If you're prescribed Mounjaro in the UK, your dose will typically start low and increase every four weeks to help your body adjust and minimise side effects. Understanding this gradual escalation process helps you know what to expect on your weight loss journey. Use our free GLP-1 weight loss calculator to see how different doses may affect potential weight loss outcomes.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Understanding Mounjaro Dose Titration
Mounjaro titration is a carefully structured dose escalation plan designed to help your body adapt to the medication. Starting with a 2.5 mg injection, your dose increases by 2.5 mg every four weeks until you reach your target maintenance dose — typically 10 mg or 15 mg depending on your individual response and tolerability.
- Week 1–4: 2.5 mg (starting dose)
- Week 5–8: 5 mg (first escalation)
- Week 9–12: 7.5 mg
- Week 13–16: 10 mg
- Week 17–20: 12.5 mg
- Week 21+: 15 mg (maximum dose)
Each dose is injected once weekly using a pre-filled KwikPen. You must remain on each dose for a minimum of four weeks before increasing — your prescriber will not escalate faster than this schedule. This gradual approach, called dose titration, reduces nausea and gastrointestinal side effects that can occur with GLP-1 and dual GIP/GLP-1 medications. Clinical trials showed that steady titration improves tolerability and helps more people reach higher effective doses.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Why Dose Increases Matter for Weight Loss
Clinical data shows that higher doses of Mounjaro are associated with greater average weight loss. In the SURMOUNT-1 trial, participants on 5 mg lost approximately 15% of body weight, while those on 15 mg lost around 20.9% — though individual results vary significantly. Your prescriber will work with you to find the optimal dose that balances weight loss benefits with side effects you can tolerate. Some people reach their weight loss goals at 10 mg and do not need further escalation. Others benefit from reaching the maximum 15 mg dose. Dose increases are only made if you are tolerating the previous dose well, so communicate with your GP or prescriber about any persistent side effects.
- 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 experience side effects during Mounjaro dose increases?
Common side effects like nausea, diarrhoea, and stomach upset often improve within a few days as your body adapts. If severe, speak to your prescriber — they may delay your next dose increase or keep you at your current dose longer to allow adjustment. Never skip doses or stop without guidance.
Can my Mounjaro dose increase be delayed or paused?
Yes. If you're experiencing significant side effects or health concerns, your prescriber can delay your next increase or pause titration at your current dose. Always inform your GP if you're struggling — dose timing is flexible based on your individual tolerance and health.
How does Mounjaro dose increase compare to Wegovy (semaglutide) titration?
Mounjaro uses larger dose steps (2.5 mg increments) and reaches a higher maximum (15 mg weekly), while Wegovy uses smaller steps (0.25–0.5 mg) and maxes at 2.4 mg weekly. Mounjaro is a dual GIP/GLP-1 agonist versus Wegovy's single GLP-1 mechanism, which may explain different titration schedules and outcomes.
Will I need to increase to the maximum 15 mg dose?
Not necessarily. Your prescriber will assess whether you're reaching your weight loss goals and tolerating your current dose well. Many people achieve effective results at 10 mg or 12.5 mg. The maximum dose isn't required for everyone — it's individualised based on your response and health profile.
Can I use the BMI calculator to track my progress during dose increases?
Yes. Our free BMI calculator and weight converter help you monitor how your weight changes as your Mounjaro dose increases over the weeks. Tracking your BMI across dose escalations shows you how the medication is working for your body.
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.