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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Mounjaro Schedule — UK Dosing and Titration Guide
Mounjaro (tirzepatide) is prescribed in the UK as a once-weekly injection with a gradual dose titration schedule starting at 2.5mg. Understanding how the dosing works, when doses increase, and what to expect from each stage helps you prepare for treatment. This guide covers the complete UK Mounjaro schedule, eligibility criteria through NHS or private prescribing, and how the dose progression supports weight management alongside a reduced-calorie diet and increased physical activity.
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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 UK Dosing Schedule and Titration Timeline
Mounjaro is prescribed as a once-weekly injection with a carefully structured dose titration. The schedule is designed to allow your body to adjust to the medication and minimise side effects.
- Week 1–4: 2.5mg weekly (starting dose)
- Week 5–8: 5mg weekly (first escalation)
- Week 9–12: 7.5mg weekly
- Week 13–16: 10mg weekly
- Week 17–20: 12.5mg weekly
- Week 21+: 15mg weekly (maximum maintenance dose)
Each dose is given as a pre-filled KwikPen injection. A minimum of 4 weeks at each dose level is required before increasing, unless your prescriber determines a different pace is appropriate. You rotate injection sites weekly between your stomach, thigh, or upper arm. If you miss a dose, you can take it within 4 days and continue your normal schedule; if more than 4 days have passed, skip that dose and resume the next scheduled injection.
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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.
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NHS Access and UK Prescribing Routes
In the UK, Mounjaro is licensed for weight management in adults with a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. NHS access is through specialist tier 3 weight management services following GP referral; availability and waiting times vary significantly by region. Private prescribing is available through UK-licensed online prescribers and GPhC-registered pharmacies without NHS referral, following a clinical assessment. Both routes require a prescription and individual eligibility assessment. Use our free GLP-1 weight loss calculator to estimate potential weight loss at different doses, and our BMI calculator to check whether you may meet initial eligibility criteria for weight management treatment.
- 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.
How long does each dose stage of Mounjaro last?
Each dose is held for a minimum of 4 weeks before increasing to the next stage. You remain on 2.5mg for weeks 1–4, then progress to 5mg for weeks 5–8, and so on. Your prescriber may adjust this timeline based on how you respond and tolerate each dose. The full escalation from starting dose to maximum (15mg) typically takes 20–24 weeks.
What happens if I miss a Mounjaro injection?
If you miss an injection, you can take it within 4 days of the scheduled date and resume your normal weekly schedule. If more than 4 days have passed, skip that dose entirely and inject on your next scheduled day. Never take two doses close together — maintain at least 72 hours (3 days) between injections. Contact your prescriber or pharmacist if you're unsure.
Can my Mounjaro dose be increased faster than the standard schedule?
The standard schedule increases every 4 weeks, but your prescriber may adjust the pace based on your individual response and tolerance. If you experience significant side effects, your prescriber may recommend staying at a dose for longer than 4 weeks. Conversely, if you tolerate a dose well, some prescribers may progress slightly faster — always follow your prescriber's specific guidance.
How is Mounjaro prescribed on the NHS in the UK?
NHS access to Mounjaro is through specialist tier 3 weight management services. You'll need a GP referral, followed by assessment by the specialist team. Availability varies by region (ICB), and waiting times can be lengthy in some areas. NICE has approved tirzepatide for use within NHS weight management services, but not all areas have current availability or capacity.
What's the difference between NHS and private Mounjaro prescribing?
NHS access is through tier 3 specialist services with a GP referral and can involve waiting lists. Private prescribing is available through online UK-licensed prescribers without NHS referral, often with faster access but at a cost. Both require a clinical assessment and prescription. Your GP can advise on NHS access in your area, or you can explore private options independently.
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