Missed a dose of Mounjaro or Wegovy? What to do (4-day rule, timing, and what NOT to do)

If you have missed your weekly injection, do not panic. This is common due to travel, busy schedules, or simply forgetting. The appropriate next step depends on your medication and the time since your scheduled dose.

This guide explains the standard missed-dose rules, including the 4-day (96-hour) rule for Mounjaro, and highlights common mistakes that may worsen side effects.

Step 1: Do not double-dose (the most common mistake)

Do not take two doses close together to make up for a missed dose. Extra medication can increase side effects such as nausea, vomiting, diarrhoea, reflux, dehydration, and dizziness. If you are unsure what counts as too close, follow the missed-dose rules below and return to your normal weekly schedule.

If you missed Mounjaro (tirzepatide): the 4-day (96-hour) rule

If you miss a dose of Mounjaro, take it as soon as you remember — only if it’s within 4 days (96 hours) of your usual injection time. If more than 4 days have passed, skip the missed dose and take your next dose on your normal scheduled day.

What NOT to do with Mounjaro

• Don’t take an extra dose to make up for the missed one.

• Do not change your injection day without a clear plan. This can lead to confusion and increase the risk of dosing too close together.

If you missed Wegovy (semaglutide): the “within 5 days” rule (plus the 48-hour check)

Missed Wegovy doses are typically managed as follows:

• If it’s been 5 days or less since your scheduled dose, take it as soon as you remember, then continue on your usual day.

• If it’s been more than 5 days, skip the missed dose and take your next dose on your usual day.

Consider the timing of your next scheduled dose:

• If your next scheduled dose is more than 48 hours away, taking the missed dose now is generally recommended in patient guidance.

• If your next dose is less than 48 hours away, skip the missed dose and wait for your normal day.

At GLP1-Approved, we frequently receive questions about missed doses, as people often seek clear guidance quickly. The primary goal is to resume your schedule safely and avoid unnecessary side effects. If you are unsure, consult your patient information leaflet, which is the official source for your specific pen and dose, and contact your prescriber or clinic for advice.

If you’ve missed more than one dose (or had a longer break)

If you have missed more than one week, especially two weeks or more, do not assume you should restart at the same dose. Side effects may be stronger after a break, and your clinician may recommend a restart plan based on your dose stage and tolerance.

When to seek medical advice urgently

Seek urgent medical attention if you experience symptoms that may indicate a serious reaction or severe dehydration, such as persistent stomach pain, repeated vomiting, dizziness, fainting, or feeling seriously unwell.

Summary of key points:

• Mounjaro: take within 4 days (96 hours); if longer, skip and resume your usual day.

• Wegovy: take within 5 days (or use the 48-hour-to-next-dose check); if longer, skip and resume your usual day.

• Never double-dose to catch up.

FAQ: Missed dose of Mounjaro or Wegovy

1) Can I take a double dose next week to catch up?
No. Do not double-dose or take two injections close together to make up for a missed dose. This can increase side effects such as nausea, vomiting, diarrhoea, and dehydration, and may be unsafe. Follow the missed-dose timing rules for your medication and return to your normal schedule.

2) Can I change my injection day after a missed dose?
Sometimes, yes, but proceed with caution. The safest approach is to take the missed dose only if you are still within the allowed window, then continue on your usual weekly day. If you wish to permanently change your injection day, consult your patient leaflet and confirm with your prescriber to avoid dosing too close together.

3) I missed more than one dose — do I restart at the same dose?
Not always. After a longer break, commonly two weeks or more, some people experience stronger side effects. Your prescriber may recommend restarting at a lower dose or repeating a step in the dose schedule, depending on your previous dose and tolerance.

4) If I skip a dose, will the medication stop working?
Missing one dose usually does not significantly affect your progress, though you may notice temporary changes in appetite or symptoms. The priority is to maintain safe, consistent weekly dosing rather than compensating with extra medication.