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 to Do If You Miss Your Mounjaro Dose by 2 Weeks
If you've missed your Mounjaro injection by 2 weeks, it's important to know what steps to take next. Mounjaro (tirzepatide) is a once-weekly GLP-1 and GIP receptor agonist prescribed in the UK for weight management, and maintaining a consistent injection schedule is important for the medication to work effectively. This guide explains what the NHS and prescribers recommend if your dose is significantly overdue, when to contact your healthcare provider, and how to get back on track with your treatment plan.
10,000+ calculations today ยท NHS-aligned thresholds ยท 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/mยฒ).
While BMI isn't a perfect measure โ it doesn't account for muscle mass, bone density, or fat distribution โ 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 โ 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.
NHS Guidance on Missed Doses and Dose Intervals
The standard guidance for Mounjaro missed doses applies when you're within 4 days of your scheduled injection day โ in this case, you simply take the dose as soon as you remember and continue with your normal weekly schedule. However, if you've missed your Mounjaro injection by more than 4 days (including 2 weeks), the approach is different.
- Skip the overdue dose โ do not take a double dose to catch up
- Resume your normal schedule โ inject on your next scheduled injection day
- Maintain minimum 72 hours between doses โ never inject less than 3 days apart
- Contact your prescriber โ if you've missed 2 weeks, inform your GP or weight management service about the gap
Missing a dose by 2 weeks means you've had a gap of approximately 21 days instead of 7 days. Your prescriber may want to review your injection schedule, check how you're managing, and assess whether you need any support to stay on track with your Mounjaro KwikPen injections going forward.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care โ 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 โ 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 โ completely free.
When to Contact Your GP or Prescriber
You should contact your GP or NHS weight management service if you've missed a Mounjaro dose by 2 weeks, especially if:
- You experienced side effects that made you delay your injection
- You've had difficulty obtaining your next KwikPen prescription
- You're unsure about your injection schedule or technique
- You're experiencing new or concerning symptoms since the missed dose
- You need support with adherence or managing your weight loss medication
If you're receiving Mounjaro through an NHS tier 3 weight management service, contact that service directly. If prescribed privately, reach out to the online prescriber or pharmacy that issued your prescription. Never delay seeking advice if you have concerns about resuming treatment after a long gap โ your healthcare team can provide personalised guidance based on your individual health and progress.
- 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 โ 5mg โ 7.5mg โ 10mg โ 12.5mg โ 15mg
- GLP-1 receptor agonist
- Up to 15โ17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg โ 0.5mg โ 1mg โ 1.7mg โ 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 | 15โ22.5% | 12โ17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20โ32 weeks | 16โ20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | ยฃ150โยฃ250/month | ยฃ150โยฃ300/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 โ 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 my Mounjaro injection by 2 weeks?
If you've missed your dose by more than 4 days (including 2 weeks), skip the overdue dose and resume your normal weekly injection schedule on your next scheduled day. Do not take a double dose. Contact your prescriber to inform them of the gap, as they may want to review your plan and discuss strategies to prevent future missed doses.
Can I take a double dose of Mounjaro to catch up?
No. You should never take a double dose of Mounjaro, even if you've missed an injection for several days or weeks. Always follow the "skip and resume" approach โ skip the overdue dose and inject on your next scheduled day, maintaining at least 72 hours between injections.
How long can I go without my Mounjaro injection?
While there's no absolute "expiry" after which the medication becomes unsafe, Mounjaro is designed as a once-weekly injection. Missing a dose by 2 weeks means a gap of about 3 weeks instead of 1 week. Extended gaps may reduce the medication's effectiveness. Always resume as soon as possible and contact your prescriber for guidance.
Will missing 2 weeks of Mounjaro affect my weight loss progress?
A 2-week gap may slightly affect your weight loss trajectory, but this varies between individuals. Some people may notice increased appetite returning during the gap. The important thing is to resume your injections and maintain the weekly schedule going forward. Your prescriber can discuss your progress and adjust your plan if needed.
Should I contact my NHS weight management service if I've missed a dose?
Yes. If you receive Mounjaro through an NHS tier 3 service, contact them to report the missed dose, explain any reasons, and confirm your next injection date. This helps them monitor your progress and provide support. If prescribed privately, contact your online prescriber or pharmacy for guidance on resuming your 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.