- Fridge: 36°F to 46°F (2°C to 8°C), in the original carton, away from light.
- Single-dose pen or vial: up to 86°F (30°C) for a total of 21 days out of the fridge.
- KwikPen or multi-dose vial: throw away after 30 days at room temperature, 30 days after first use, or 4 doses.
- No need to warm it before injecting.
- Never freeze it. Frozen Mounjaro must be thrown away.
In the fridge
Store Mounjaro in the refrigerator at 36°F to 46°F (2°C to 8°C), in its original carton to protect it from light.[1, 2] Keep it away from the freezer compartment and the cold plate at the back of the fridge, where things can freeze.
You do not need to take a single-dose pen out early to warm up. The pen instructions say it is not necessary to warm it to room temperature.[2]
How long Mounjaro can be out of the fridge
| Device | Room temperature (up to 86°F) | Then |
|---|---|---|
| Single-dose pen | Total of 21 days | Throw it away |
| Single-dose vial | Total of 21 days | Throw it away |
| KwikPen or multi-dose vial | Up to 30 days | Throw away at 30 days, 30 days after first use, or after 4 doses |
From the Mounjaro prescribing information.[1]
"Room temperature" here has a ceiling of 86°F. A hot car, a sunny windowsill or a beach bag can go well above that. The label says to protect Mounjaro from heat and light.[1]
Can you put Mounjaro back in the fridge?
The single-dose rule is a total of 21 days at room temperature.[1] That means the days add up across separate stretches: three days out on one trip and five on another count as eight. Write the date on the carton each time a pen or vial leaves the fridge, so you know when you reach 21.
Mounjaro KwikPen and multi-dose vial
The KwikPen and multi-dose vial each hold four weekly doses. Unopened, they belong in the fridge. If an unopened one is kept at room temperature (up to 86°F), throw it away after 30 days. Once opened, throw it away after a total of 30 days at room temperature, 30 days after first use, or after 4 weekly doses, whichever comes first, even if medicine is left.[1]
Frozen, hot or dropped
- Frozen: do not use it, even after it thaws.[2]
- Dropped single-dose pen: if it falls on a hard surface, do not use it. Use a new pen.[2]
- Got too hot, or you lost count of the days: the label gives no exception. Ask your pharmacist before you use it.
Common questions
Does Mounjaro need to be refrigerated?
Yes, until you need it. The prescribing information says to store Mounjaro in the refrigerator at 36°F to 46°F (2°C to 8°C), in the original carton to protect it from light. Single-dose pens and vials can then spend a total of 21 days at room temperature up to 86°F (30°C).
How long can Mounjaro be out of the fridge?
A single-dose pen or single-dose vial can be kept unrefrigerated up to 86°F (30°C) for a total of 21 days. A Mounjaro KwikPen or multi-dose vial must be thrown away after a total of 30 days at room temperature, 30 days after first use, or after 4 weekly doses, whichever comes first.
Can I put Mounjaro back in the fridge?
The 21-day allowance for single-dose pens and vials is a total, so days out of the fridge add up. Keep count, and throw the pen or vial away once the total reaches 21 days. If you are unsure, ask your pharmacist.
Does Mounjaro need to be at room temperature before injecting?
No. The single-dose pen instructions say it is not necessary to warm the pen to room temperature before you inject.
What happens if Mounjaro freezes?
Do not use it. The instructions say to throw away a pen that has been frozen, even if it has thawed.
Sources
- Eli Lilly and Company. Mounjaro (tirzepatide) Prescribing Information. Revised 08/2026. Last checked 2026-10-01.
- Eli Lilly and Company. Mounjaro single-dose pen Instructions for Use. Revised April 2026. Last checked 2026-10-01.