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
Can You Skip A Week On Mounjaro?
If you're taking Mounjaro (tirzepatide), you may wonder what happens if you skip a week or miss a scheduled injection. The short answer is: you should not intentionally skip doses. However, if you do miss an injection, there are safe steps to follow. This guide explains what the prescribing information says, how missing a dose affects your treatment, and what you should do if it happens. Always speak to your GP or prescriber if you have concerns about your Mounjaro schedule.
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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.
What The Guidelines Say About Missed Mounjaro Doses
According to the UK prescribing information, Mounjaro is designed as a once-weekly injection that you should take on the same day each week. The medication works best when taken at regular intervals.
If you miss a Mounjaro injection, the guidance is clear:
- Within 4 days of your scheduled dose: Take your injection as soon as you remember, then continue your normal weekly schedule from that point.
- More than 4 days late: Skip the missed dose entirely and take your next injection on your normal scheduled day.
- Minimum gap: Never take two doses within 72 hours (3 days) of each other.
This guidance applies whether you're on 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or the maximum 15 mg tirzepatide dose. Your prescriber may give you slightly different advice based on your individual circumstances.
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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.
Why You Shouldn't Intentionally Skip Weeks
Intentionally skipping a week or stopping Mounjaro suddenly can disrupt your weight management progress and affect how the medication works. Regular, consistent dosing helps maintain steady appetite control and support your weight loss goals.
If you're considering stopping Mounjaro, skipping doses, or changing your injection schedule, contact your prescriber or GP first. They can:
- Discuss your reasons for wanting to skip or stop
- Explain any risks of stopping suddenly
- Adjust your dose if you're experiencing side effects
- Help you plan a safe transition if you want to discontinue treatment
Track your progress with our free progress tracker to see how consistent dosing supports your weight management journey.
- 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 happens if I miss one Mounjaro injection?
If you miss a dose within 4 days, take it as soon as you remember and continue your normal schedule. If you miss it by more than 4 days, skip that dose and take your next one on your regular day. Never double-dose. Contact your prescriber if you're unsure.
Can I skip a week intentionally to avoid side effects?
You should not intentionally skip doses. If you're struggling with side effects, speak to your GP instead. They may reduce your dose, slow your dose titration, or adjust your treatment plan rather than having you skip weeks.
How often should I take Mounjaro?
Mounjaro is a once-weekly injection prescribed to be taken on the same day each week. This consistent schedule helps the medication work effectively. Use a reminder app or calendar to help you stay on track.
What if I want to stop taking Mounjaro?
Do not stop suddenly without speaking to your prescriber. They can discuss your reasons, review your progress, and help you safely stop if needed. Stopping without guidance may cause rapid weight regain and other changes.
Does missing one week of Mounjaro affect my weight loss?
Missing one dose may slightly slow your progress, but won't derail your efforts completely. However, consistent dosing gives the best results. If you miss a dose, take it as directed and resume your normal schedule — your prescriber can advise if you're concerned about progress.
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.