Insulin can freeze if exposed to very low temperatures, similar to how water freezes. If insulin freezes, it is generally not recommended to use it after thawing. Insulin manufacturers like NovoLog, Apidra, Humalog, Lantus, and Levemir all advise against using insulin that has been frozen, as it loses its potency. Studies and health organizations also support this, indicating that frozen insulin is less effective. While some types of insulin might survive freezing and thawing better than others, it is safest to replace any insulin that has been frozen to ensure proper diabetes management.