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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What Is The Best Dose Of Mounjaro For Weight Loss?
There is no single "best" dose of Mounjaro for weight loss — the right dose depends on your individual health, tolerance, and response to the medication. Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection that starts at 2.5 mg and increases gradually over weeks, with a maximum dose of 15 mg. Your prescriber will assess you and recommend a dose plan tailored to your specific circumstances. Clinical trials showed that higher doses produced greater average weight loss, but results vary significantly between individuals.
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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
Mounjaro uses a dose titration schedule, meaning you start low and increase gradually. Each dose is held for a minimum of 4 weeks before escalation:
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg (first escalation)
- Weeks 9–12: 7.5 mg
- Weeks 13–16: 10 mg
- Weeks 17–20: 12.5 mg
- Week 21+: 15 mg (maximum dose)
This gradual approach allows your body to adjust and helps your prescriber monitor tolerability. Not everyone escalates to the maximum — some individuals reach effective weight loss at lower doses like 5 mg or 10 mg and choose to continue there. Your GP or prescriber will assess your progress and side effects at each stage, adjusting if needed. The dose titration schedule is standard across NHS specialist services and private prescribing in the UK.
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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.
Weight Loss Results By Dose — What The Evidence Shows
The SURMOUNT-1 clinical trial compared weight loss outcomes at different Mounjaro doses over 72 weeks, alongside reduced-calorie diet and increased physical activity:
- 5 mg dose: approximately 15% average body weight loss
- 10 mg dose: approximately 19.5% average body weight loss
- 15 mg dose: approximately 20.9% average body weight loss
However, individual results varied widely — some participants lost more at lower doses, others needed higher doses. Your prescriber will balance efficacy with tolerability and cost. If you're experiencing side effects, a lower dose may be maintained long-term rather than escalating to maximum. Use our GLP-1 weight loss calculator to estimate potential weight loss at different doses based on your starting weight.
- 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.
Does everyone need to reach the 15 mg maximum dose of Mounjaro?
No. Some people achieve effective and sustainable weight loss at 5 mg, 10 mg, or 12.5 mg and choose to stay at that dose long-term. Your prescriber will recommend escalating only if you're tolerating the current dose well and want further weight loss. There's no medical requirement to reach 15 mg if a lower dose is working for you.
What if I can't tolerate a higher Mounjaro dose?
If side effects become unmanageable at a higher dose, your prescriber may recommend staying at your current dose or stepping back to a previous dose. Weight loss is still possible at lower doses — clinical trials showed meaningful results even at 5 mg. Your prescriber will work with you to find the right balance between efficacy and tolerability.
How long does Mounjaro dose titration take?
The full titration schedule to maximum dose (15 mg) takes approximately 20 weeks. However, many people reach their target weight loss before reaching maximum dose. Your prescriber may slow titration or pause at a lower dose if you're seeing good results and tolerating it well. There's no fixed timeline — it's individualised.
Is Mounjaro dose the same as Wegovy dose?
No. Mounjaro (tirzepatide) and Wegovy (semaglutide) are different medications with different mechanisms and dose ranges. Mounjaro doses range from 2.5 mg to 15 mg weekly. Wegovy doses range from 0.25 mg to 2.4 mg weekly. Approximate equivalents exist (5 mg Mounjaro ≈ 0.5 mg Wegovy), but they're not interchangeable — only your prescriber can advise which is suitable for you.
Will my prescriber start me on a specific Mounjaro dose based on my weight?
All UK prescriptions of Mounjaro for weight loss start at 2.5 mg regardless of your starting weight. However, your prescriber will consider your BMI, health conditions, previous medication tolerance, and kidney function when deciding on your escalation schedule and target dose. Individual factors may mean you escalate faster or slower than the standard 4-week schedule.
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.