How long does tirzepatide last in the fridge? See how long it keeps unopened, how long it can stay out, and how to tell if it has gone bad.
An unopened tirzepatide pen or vial lasts in the fridge until the expiration date on its label, as long as it stays between 36 and 46°F (2 to 8°C). That is what the FDA-approved brand, Zepbound, says. Once it is out of the fridge or opened, the clock is much shorter, and compounded vials follow the date on your pharmacy’s label.
This article is general information, not medical advice or a dose recommendation. Your prescribing provider and pharmacy set the rules for your own supply.
How long does tirzepatide last in the fridge?
Unopened, it lasts until the expiration date printed on the label. The Zepbound prescribing information says to keep unopened pens and vials in a refrigerator at 36 to 46°F (2 to 8°C) and to keep them in the original carton, because light and heat can harm the medicine. It also says not to freeze it.
Zepbound is the FDA-approved brand of tirzepatide for weight loss. Mounjaro is the same medicine sold for type 2 diabetes. Compounded tirzepatide is not FDA-approved and has no official label of its own, so we explain it separately below.
How long can tirzepatide stay out of the fridge?
For a short time, yes. The Zepbound label allows storage at room temperature, up to 86°F (30°C), when needed. How long depends on the form:
| Zepbound form | In the fridge (36 to 46°F) | At room temperature (up to 86°F) |
|---|---|---|
| Single-dose pen or single-dose vial | Until the expiration date | Up to a total of 21 days, then throw it away |
| Unopened multi-dose vial or KwikPen | Until the expiration date | Throw away after 30 days |
| Opened multi-dose vial or KwikPen | Up to 30 days after first use, or 4 weekly doses | Throw away after a total of 30 days |
The days add up. Two days on a counter today and three days in a bag next week count as five days. MedlinePlus adds that single-dose pens or vials that have been stored at room temperature should not go back in the refrigerator.
How long does an opened vial last?
On the Zepbound label, an opened multi-dose vial or KwikPen is thrown away after a total of 30 days at room temperature, 30 days after first use, or after four weekly doses, even if there is medicine left in it. Whichever comes first applies.
Opened vials are not all the same, so go by the instructions that came with yours. The clinic’s own guide to tirzepatide units by vial strength covers the vial sizes the clinic’s pharmacies supply.
What about compounded tirzepatide vials?
Compounded medicines are made by a pharmacy and are not FDA-approved, so there is no Zepbound-style label to quote for them. What we can say comes from the clinic’s own published guidance: compounding pharmacies recommend that multi-dose vials be used within 28 days unless the vial has been tested to last longer. For larger vials, go by the beyond-use date printed on the vial itself.
The most reliable rule is simple. Read the storage line and the date on your own vial label, and ask your provider or pharmacy if anything is unclear. The label on your vial overrides anything in a general article, including this one. The quantity planner shows how the clinic’s pharmacies size their vials, and the vial calculator helps you plan your weeks.
How can you tell if tirzepatide is still good?
Check the date first, then look at the liquid. The Zepbound instructions say the medicine should be clear and colorless to slightly yellow. Do not use it if it:
- is past the expiration date,
- has been frozen,
- looks cloudy,
- has particles in it, or
- has changed color.
If you are unsure, do not guess. Contact your pharmacy or provider before you inject.
What about heat, travel and power cuts?
The label gives two limits you can plan around: protect the medicine from heat and light, and keep it from freezing. Room temperature storage is only allowed up to 86°F, and a hot car is well above that. Keep the original carton with you so the label and date travel with the medicine.
If a cooler is cold enough to freeze the medicine, that is a problem too. If you cannot say how long tirzepatide spent warm or whether it froze, ask your pharmacy before using it. They can tell you what to do for your specific product.
Frequently asked questions
How long does tirzepatide last in the fridge?
Unopened Zepbound pens and vials last until the expiration date on the label when kept at 36 to 46°F in the original carton. Opened multi-dose vials are thrown away after 30 days or four weekly doses on the Zepbound label. Compounded vials follow the date on your pharmacy’s label.
Can tirzepatide be left out overnight?
Within the label’s allowance, yes. Zepbound can be kept at room temperature up to 86°F for a total of 21 days for single-dose pens and vials, or 30 days for multi-dose forms. Count every day it is out, and keep it away from heat and light.
Can you put tirzepatide back in the fridge after it has been out?
MedlinePlus says single-dose pens and vials that were stored at room temperature should not be returned to the refrigerator. The label counts the total days at room temperature, so the clock does not reset. Ask your pharmacy if you are unsure.
What happens if tirzepatide freezes?
Do not use it. The Zepbound label says not to freeze the medicine and not to use it if it has been frozen. Contact your pharmacy for a replacement.
Does compounded tirzepatide need to be refrigerated?
Follow the storage line on your own vial label. Compounded medicines have no FDA label, and the clinic’s pharmacies recommend using multi-dose vials within 28 days unless the vial has been tested to last longer. Ask your provider or pharmacy if the label is not clear.
How can you tell if tirzepatide has gone bad?
Check the date, then look at it. It should be clear and colorless to slightly yellow. Do not use it if it is cloudy, has particles, has changed color or has been frozen.
Is it safe to take tirzepatide that is a few days past its date?
The label sets the expiration date, and the safe choice is not to use medicine past it. Ask your pharmacy or provider before using anything that has expired.
More from this guide series
Next step
To find out whether tirzepatide is right for you, see the clinic’s tirzepatide programs or start the free intake form. The clinic will contact you to schedule an appointment, and your prescribing provider will tell you how to store your supply.