Short answer: Keep unopened Lantus in the fridge at 36-46°F (2-8°C); it lasts until the expiration date there, or 28 days at room temperature up to 86°F (30°C). An opened vial lasts 28 days in the fridge or below 86°F. An in-use SoloStar pen lasts 28 days at room temperature only; do not put it back in the fridge. Throw away Lantus that froze. Source: Lantus label, section 16.2.
Section 16.2: “Store unused LANTUS in a refrigerator between 36°F and 46°F (2°C and 8°C). Do not freeze. Discard LANTUS if it has been frozen. Protect LANTUS from direct heat and light.”
| Form | Unopened, refrigerated | Unopened, room temp (up to 86°F) | In use (opened) |
|---|---|---|---|
| 10 mL multiple-dose vial | Until expiration date | 28 days | 28 days, refrigerated or room temperature |
| 3 mL SoloStar pen | Until expiration date | 28 days | 28 days, room temperature only (do not refrigerate) |
The label says so: in-use SoloStar pens are “Room temperature only (Do not refrigerate).” The pen Instructions for Use: “Keep your pen at room temperature below 86°F (30°C). Do not put your pen back in the refrigerator.” They also suggest taking a new pen out at least 1 hour before injecting, because cold insulin is more painful to inject.
“Only use your pen for up to 28 days after its first use. Throw away the LANTUS SoloStar pen you are using after 28 days, even if it still has insulin left in it.”
Many GLP-1 users also take insulin; see semaglutide and insulin.
Vial Instructions for Use: “If a vial has been frozen or overheated, throw it away.” Section 16.2 says discard Lantus if it has been frozen. Room-temperature storage stops at 86°F (30°C).
Opened Lantus can travel at room temperature, below 86°F (30°C), for the rest of its 28 days. Unopened spares should stay cold, or they start their own 28-day room-temperature clock.
More in the travel guide.