Insulin Storage: How to Keep Your Insulin Safe and Effective

When you use insulin, a life-saving hormone used to manage diabetes by regulating blood sugar. Also known as injectable glucose-lowering medication, it only works if stored correctly. A single mistake—like leaving it in a hot car or freezing it—can make it useless, and that’s not just inconvenient, it’s dangerous.

Most unopened insulin, a vial or pen that hasn’t been pierced yet. Also known as pristine insulin, it needs to stay between 36°F and 46°F (2°C to 8°C). That means your fridge is ideal, but never put it in the freezer. Once you start using it, the rules change. Most opened insulin can stay at room temperature—up to 86°F (30°C)—for 14 to 28 days, depending on the type. Check the label. Some, like Lantus or Tresiba, last longer. Others, like Humalog, don’t. This isn’t guesswork. It’s science backed by manufacturers and the FDA, the U.S. agency that sets drug safety and labeling standards. Also known as U.S. Food and Drug Administration, it requires all insulin packaging to list exact storage instructions because getting it wrong can lead to high blood sugar, diabetic ketoacidosis, or worse.

Traveling? Insulin doesn’t like extreme heat or cold. Don’t leave it in a glove compartment. Don’t let it freeze in a winter coat pocket. Use an insulated cooler with a cold pack, but never let the insulin touch ice. Airport security won’t let you check it in luggage—carry it with you. And always bring extra. If your insulin looks cloudy when it shouldn’t, has clumps, or changed color, toss it. No exceptions. You wouldn’t drink expired milk. Don’t use expired insulin. The insulin storage rules aren’t suggestions. They’re the difference between staying healthy and ending up in the ER. Below, you’ll find real advice from people who’ve been there—how to handle insulin on road trips, what to do when the power goes out, and which brands hold up best when things go wrong.