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 for 2 Weeks
If you've missed your Mounjaro (tirzepatide) injection for 2 weeks, you're beyond the standard 4-day grace period and need to speak with your prescriber immediately. Missing a dose can affect your weight loss progress and symptom control, but it's not a medical emergency. Your GP or weight management clinic will advise whether to take the next scheduled dose, skip to your normal routine, or adjust your schedule. Understanding the correct action now helps you get back on track safely.
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 Missed Dose Guidance vs Wegovy Comparison
Mounjaro (tirzepatide) is a once-weekly GLP-1 and GIP dual agonist requiring very precise timing for best results. Missing a dose by 2 weeks means you've gone 19 days since your last injection — well beyond the recommended 4-day window. In contrast, Wegovy (semaglutide) is also a once-weekly GLP-1 injection with similar missed-dose guidelines, though the underlying mechanisms differ slightly.
Both medications work through appetite regulation and blood sugar control, but tirzepatide's dual GIP+GLP-1 action may provide slightly different side effect profiles and weight loss patterns compared to Wegovy's single GLP-1 mechanism. Clinical trial data (SURMOUNT vs STEP trials) showed both are effective, but individual responses vary significantly. The key difference in a missed-dose situation: both require prompt prescriber guidance to resume safely and avoid complications like rebound appetite or dose confusion.
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.
What Your Prescriber Will Recommend
When you contact your GP or weight management clinic about a 2-week missed dose, they will typically ask: when was your last injection, have you experienced any symptoms, and are you ready to restart? Most prescribers will advise you to take your next scheduled dose as planned rather than "catching up," then continue your normal weekly schedule.
Do not double-dose or inject twice to make up for the missed week. Your prescriber may also review whether any side effects or barriers prevented you taking the dose — this helps them support you better going forward. If you've been waiting longer than 4 days after the missed date, resuming on schedule is safest. Use our free GLP-1 weight loss calculator to track your progress once you're back on track, and consider setting phone reminders to help prevent future missed doses.
- 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's the maximum time between Mounjaro doses?
Each dose should be taken once weekly. The standard guidance is to inject within a 4-day window of your scheduled day. If you miss by more than 4 days (as in a 2-week miss), contact your prescriber for instructions rather than doubling up.
Is missing Mounjaro for 2 weeks dangerous?
A 2-week miss is not a medical emergency, but it disrupts your treatment. You may experience increased appetite, fluctuating blood sugar, or reduced weight loss effectiveness. Contact your GP or weight management clinic immediately for guidance on safely resuming.
How does Mounjaro's missed-dose protocol compare to Wegovy?
Both Mounjaro and Wegovy follow the same core guidance: inject once weekly within a 4-day window. If you miss by more than 4 days, skip that dose and resume your normal schedule. Neither should be double-dosed. Always consult your prescriber for individual advice.
Will missing a dose for 2 weeks affect my weight loss?
Yes, missing 2 weeks of tirzepatide will likely pause or reverse some weight loss progress. Appetite regulation and blood sugar control slip without the weekly dose. Once you resume, your body will adjust back, though individual timelines vary. Your prescriber can advise on recovery expectations.
Should I skip the next dose after a 2-week miss?
No — contact your prescriber first. Most will advise you to resume your normal weekly schedule immediately, not skip the following dose. Skipping could extend the gap further. Your prescriber may adjust timing based on your circumstances, so get their guidance before injecting.
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.