Updated October 2, 2026

How long does insulin last out of the fridge?

Most insulin lasts 28 days out of the fridge at up to 86°F (30°C), opened or not. The exceptions run both ways: a Humulin N KwikPen gets 14 days, Humulin vials 31, and Toujeo and Tresiba 56. Many insulin pens, once opened, should not go back in the fridge. Frozen insulin should never be used.

Room-temperature days, by insulin

Every label below says unopened insulin belongs in the fridge at 2–8°C (36–46°F) until its expiration date, and every room-temperature allowance tops out at 86°F (30°C).

Insulin	Unopened, room temp	Opened, in use	Back in the fridge once opened?
Lantus	28 days	28 days	Vial: yes. SoloStar pen: no
Basaglar	28 days	28 days	No
Toujeo	Not listed	56 days	No
Tresiba	56 days	56 days	Yes
Humalog	28 days	28 days, counting unopened days	Vial: yes. Pens and cartridges: no
NovoLog	28 days	28 days	Vial: yes. PenFill, FlexPen, FlexTouch: no
Admelog	28 days	28 days	Vial: yes. SoloStar pen: no
Fiasp	28 days (PumpCart 18)	28 days	Vial and FlexTouch: yes. PenFill and PumpCart: no
Lyumjev	28 days	28 days, counting unopened days	Vial: yes. Pens and cartridges: no
Humulin R U-100 vial	31 days	31 days, counting unopened days	Not stated
Humulin N vial	31 days	31 days	Not stated
Humulin N KwikPen	14 days	14 days	No
Levemir (discontinued in the US)	42 days	42 days	FlexPen: no

Awiqli, the weekly insulin, is the outlier: the FDA lists it at room temperature below 86°F for up to 12 weeks.

The clock can start before you open it

Humalog, Lyumjev and Humulin R count the days in total. Humalog's label says a pen “can only be used for a total of 28 days, including both not in-use (unopened) and in-use (opened).” A pen that sat in a warm bag for ten days before you opened it has 18 left, not 28.

Why most pens stay out once opened

The label tables for Lantus SoloStar, NovoLog FlexPen, Humalog pens and others say “Room temperature only (Do not refrigerate)” once in use. Vials can usually go either way. Tresiba and Fiasp FlexTouch are the pens that allow both. The table above has the split for each one.

What the FDA says about heat

The FDA's emergency guidance says insulin in vials or cartridges, opened or unopened, “may be left unrefrigerated at a temperature between 59°F and 86°F for up to 28 days and continue to work.” Above that, “the longer insulin is exposed to extreme heat or cold, the less effective it becomes.”

If you cool insulin with ice, the FDA says to avoid freezing it, and not to use insulin that has frozen.
Insulin in a pump that gets above 98.6°F should be thrown away.
Once you can get properly stored insulin again, the FDA says to replace any vials that were exposed to extreme temperatures.

When 86°F is the problem

The room-temperature days only hold while the room stays under 86°F. A summer car, a beach day or a power cut can all pass it. Our guide to keeping insulin cold without a fridge compares ice packs, evaporative wallets and battery coolers, and flying with insulin covers the TSA rules.

Sources

This guide quotes manufacturer labels and government pages, linked above. Labels change, so the leaflet in your box and your pharmacist have the final word. VialCool sells an empty cooler, not medication.

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