Not in-use (unopened): Humulin R not in-use should be stored in a refrigerator (2° to 8°C [36° to 46°F]), but not in the freezer. Do not use Humulin R if it has been frozen.
In-use: Humulin R bottles in-use should be refrigerated. If refrigeration is not possible, the bottle of Humulin R that you are currently using can be kept unrefrigerated as long as it is kept at room temperature (below 30°C [86°F]), and away from heat and light. Do not use Humulin R if it has been frozen.
Do not use a bottle of Humulin R after the expiration date stamped on the label.