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
What Is the Maximum Dose of Mounjaro?
The maximum dose of Mounjaro (tirzepatide) available in the UK is 15 mg once weekly. Most people start at a lower dose and increase gradually over several months in a process called dose titration. Your prescriber will adjust your dose based on how your body responds and your individual tolerance to the medication. The goal is to find the lowest effective dose that helps you achieve your weight loss goals while minimising side effects. Not everyone needs to reach the maximum dose—many people find good results at 5 mg, 10 mg, or 12.5 mg. Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses.
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.
Mounjaro Dose Titration Schedule in the UK
Mounjaro is prescribed as a stepped dose titration, with each dose increase happening every 4 weeks minimum. Here's how the standard UK titration schedule works:
- Weeks 1–4: 2.5 mg once weekly (starting dose)
- Weeks 5–8: 5 mg once weekly
- Weeks 9–12: 7.5 mg once weekly
- Weeks 13–16: 10 mg once weekly
- Weeks 17–20: 12.5 mg once weekly
- Week 21 onwards: 15 mg once weekly (maximum dose)
Your prescriber may slow this schedule if you experience side effects or speed it if your body tolerates increases well. Some people plateau at 5 mg or 10 mg and don't need to go higher—this is completely normal. Each Mounjaro KwikPen contains 4 weeks of doses, so a full titration to maximum takes roughly 5–6 months. The dose titration approach helps your body adjust gradually and reduces the severity of common side effects like nausea.
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.
Cost and Access in the UK: NHS vs Private Routes
NHS access: Mounjaro is available through specialist tier 3/4 weight management services, but availability varies significantly by region. NHS access typically involves a referral from your GP and assessment by a specialist team. Waiting lists can be lengthy in many areas, sometimes 6–12 months or longer. Once prescribed through the NHS, there is no cost to you.
Private access: Mounjaro is available through UK-licensed online prescribing services following a clinical assessment. Private costs vary by dose and provider but typically range from £129–£320 per month. You'll complete an online health questionnaire, receive an assessment from a UK-registered prescriber, and if approved, a prescription is dispensed by a GPhC-registered pharmacy. This route offers faster access without NHS waiting lists, though it requires out-of-pocket payment.
- 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.
Do I have to reach the 15 mg maximum dose?
No. The maximum dose is 15 mg, but many people achieve good weight loss results at lower doses like 5 mg, 10 mg, or 12.5 mg. Your prescriber will assess how you're responding and may recommend staying at a dose that's working well for you rather than increasing further. The goal is finding the right dose for your individual needs, not necessarily reaching the maximum.
What happens if I can't tolerate a higher dose?
If you experience side effects that are too uncomfortable, you can stay on your current dose or reduce to a previous dose. Your prescriber may slow the titration schedule or recommend pausing before your next increase. This is normal—many people manage their weight loss effectively without reaching the maximum dose.
How long does it take to reach maximum dose?
Following the standard titration schedule, it takes approximately 5–6 months to reach the 15 mg maximum dose, since you increase every 4 weeks. However, this timeline can be adjusted based on your individual response and tolerance. Some people may titrate faster, while others may take longer between increases.
Is the cost different at higher doses of Mounjaro?
Yes, private costs typically increase with higher doses. A 5 mg dose costs less than a 15 mg dose through private providers. NHS access has no cost difference once you're approved. Check with your prescriber about the specific cost at your target dose, as pricing varies by provider and region.
Can I skip doses during titration?
No, you shouldn't skip doses in the titration schedule. Each dose step allows your body to adjust. If you miss a dose, take it within 4 days if possible and continue your normal schedule. Missing or skipping intentionally could affect the consistency of your weight loss results—always follow your prescriber's recommendations.
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.