Insulin is a hormone produced by the pancreas that manages blood sugar levels. For individuals with diabetes, manufactured insulin is a necessary medication because their bodies either don’t produce enough or can’t use it effectively. It helps transport glucose into cells, providing energy and preventing complications from high blood sugar. This external supply is crucial for maintaining overall health and controlling diabetes.
Why Freezing Harms Insulin
Insulin is a delicate protein highly sensitive to temperature extremes. When insulin freezes, typically at or below 0°C (32°F), it undergoes irreversible physical and chemical changes that compromise its structure and effectiveness. The primary issue is the formation of ice crystals, which physically damage the insulin molecules. This process breaks down the protein, leading to a loss of its biological activity.
Freezing can also cause insulin proteins to aggregate or denature, meaning they unfold or clump together. This structural damage renders the medication ineffective at lowering blood sugar levels, even if it thaws and appears normal. Using compromised insulin can lead to unpredictable blood sugar control, potentially causing dangerously high or low glucose levels. Manufacturers universally advise against using insulin that has been frozen. Signs that insulin may have been frozen include a cloudy appearance, the presence of clumps, or visible white particles.
Storing Insulin Correctly
Proper storage is important to maintain insulin’s stability and effectiveness. Unopened insulin vials or pens should be kept refrigerated at temperatures between 2°C and 8°C (36°F and 46°F) until their expiration date. It is advisable to store insulin away from the refrigerator’s freezer compartment, as temperatures in this area can fluctuate and lead to accidental freezing.
Once opened or in use, most insulin can be stored at room temperature, typically between 15°C and 30°C (59°F and 86°F), for up to 28 days, though specific durations may vary by manufacturer and insulin type. If insulin accidentally freezes, it should be immediately discarded and never used, even if it thaws.
Preventing insulin from freezing requires careful handling, especially in cold environments or during travel. Avoid leaving insulin in places where temperatures can drop significantly, such as a car overnight in winter or near a freezer pack without proper insulation. When traveling in cold weather, keeping insulin close to the body, perhaps in an inside pocket, can use body heat to prevent it from reaching freezing temperatures. Specialized insulated cases or wallets designed for insulin can also provide a protective barrier against temperature extremes.