Can You Take Mounjaro When You Have the Flu?

Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist taken as a once-weekly injection. One of its commonly reported effects is slower stomach emptying, which can already contribute to nausea in some people — particularly after a dose increase. When you have the flu, you may already be experiencing nausea, vomiting, reduced appetite, and dehydration. Combining these with Mounjaro's gastrointestinal effects means symptoms could feel more intense than usual.

Dehydration is a particular consideration

Flu can cause fever and sweating, which increases the risk of dehydration. Vomiting and diarrhoea — whether from the flu or from Mounjaro-related side effects — can compound this further. Staying well hydrated is generally important for anyone on tirzepatide, and illness makes this harder. If you are unable to keep fluids down, contact your healthcare professional promptly.

Your prescriber decides whether to pause or continue

Some people on GLP-1 medicines are advised by their prescriber to delay a dose during periods of significant illness — but this is an individual clinical decision, not a general rule. Never skip, delay, or take an extra dose without guidance from your prescriber or doctor. The decision depends on your overall health, what other medicines you may be taking, and how unwell you are. For a broader look at circumstances that might affect your Mounjaro schedule, the how Mounjaro works guide covers the medicine's mechanism in more detail.

It is also worth knowing that Mounjaro carries a black triangle (▼) designation in some countries, meaning any new or worsening side effects should be reported to your national reporting scheme (such as the UK's Yellow Card scheme) as well as to your healthcare professional.

If you have questions about other situations where taking Mounjaro requires extra thought, you may find it helpful to read about taking Mounjaro with gallstones or what to do if your injection day shifts — both situations where your prescriber's guidance is equally important.

When you are unwell, keeping track of how you feel and what you have taken becomes more valuable — not less. GLP Trackr's side-effect tracker lets you log symptoms like nausea, fatigue, and dizziness day by day, so you can see whether your experience during illness differs from your usual pattern. That record can be genuinely useful when you speak to your prescriber about what happened.

The app's dose logging feature means you have a clear, time-stamped record of every injection — including if you delayed one while ill or took it as normal. Rather than trying to recall the timeline from memory at your next appointment, you can show your prescriber exactly what occurred. This is particularly helpful for general questions about taking Mounjaro safely in different circumstances.

GLP Trackr also has a daily check-in where you can record your energy levels, mood, and how you are feeling overall — useful context to build up during a period of illness so nothing is lost before your next conversation with your healthcare team.

GLP Trackr is a tracking tool, not a substitute for medical advice. If your symptoms are severe, persistent, or you are concerned — particularly if you cannot keep fluids down, or you experience chest pain, severe abdominal pain, or signs of a serious reaction — contact your healthcare professional promptly. Do not rely on a tracking app in a situation that needs clinical attention.

Log your symptoms, keep your prescriber informed, and let GLP Trackr hold the record. Download it free on the App Store or Google Play and begin a 7-day trial at no cost.