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 Often Do You Take A Mounjaro Maintenance Dose?
Mounjaro (tirzepatide) is taken as a once-weekly injection, including during the maintenance phase. After your prescriber has found your effective dose through a dose titration process, you continue injecting once every seven days at that same maintenance dose. In the UK, Mounjaro is a prescription-only medicine accessed through NHS specialist services or private online prescribing. Your GP or prescriber will advise on your personal maintenance schedule based on your response to treatment and health needs.
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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.
Mounjaro Maintenance Dose Schedule And Duration
Once you reach your maintenance dose of Mounjaro, the injection frequency remains consistent: once every seven days. The dose titration process typically takes 16–20 weeks, during which you increase gradually from 2.5 mg up to your target dose. Common maintenance doses are 10 mg or 15 mg weekly, though 5 mg or 7.5 mg may be sufficient for some individuals.
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg (first escalation)
- Weeks 9–12: 7.5 mg (if needed)
- Weeks 13–16: 10 mg (if needed)
- Weeks 17–20+: 15 mg (maximum maintenance)
Each Mounjaro KwikPen contains four pre-filled doses, providing a four-week supply. Your prescriber will monitor your response and may adjust your maintenance dose if needed, but the weekly injection schedule remains unchanged throughout treatment.
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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.
How Long Do You Stay On Mounjaro Maintenance?
The duration of Mounjaro maintenance depends on your individual health goals and prescriber's assessment. There is no fixed "end date" — some patients continue indefinitely if they are responding well and tolerating the medication. If you stop Mounjaro, weight regain may occur, which is why ongoing treatment is often recommended as part of a sustained weight management plan alongside lifestyle changes.
Your GP or specialist can discuss whether Mounjaro is right for you long-term. Use our free GLP-1 weight loss calculator to estimate potential weight loss at different doses, and our BMI calculator to track your progress against NHS healthy weight targets.
- 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.
Is Mounjaro always injected once per week?
Yes. Once you reach your maintenance dose, you inject once every seven days. The once-weekly schedule applies throughout the dose titration phase and the maintenance phase. Missing a dose or changing the schedule should only be done on your prescriber's advice.
What happens if I miss a weekly Mounjaro injection?
If you miss your injection within 4 days, take it as soon as you remember and resume your normal weekly schedule. If it is more than 4 days since you were due your injection, skip that dose and take your next injection on your normal scheduled day. Never double up on doses.
Can my maintenance dose of Mounjaro change?
Yes. Your prescriber may adjust your maintenance dose up or down based on how well you are responding, any side effects, or changes in your health. However, the once-weekly injection frequency remains the same — only the dose strength (measured in mg) may change.
How do I know what my maintenance dose should be?
Your prescriber determines your maintenance dose during the titration phase by starting at 2.5 mg and gradually increasing every 4 weeks. Your dose depends on your response to treatment, tolerability of side effects, and individual health factors. The maximum licensed dose is 15 mg weekly, but many patients respond well at 10 mg.
Is Mounjaro available on the NHS in the UK?
NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services (tier 3). NHS access is through specialist referral and varies by region and availability. Many patients access Mounjaro privately via UK-licensed prescribers without an NHS referral, though this involves private costs.
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.