Never expose insulin to extreme temperatures like the freezer or the hot sun (or inside your car on a summer day). These changes in temperature could affect its potency. Also check the expiration date just like you would with any other medication. Don’t use insulin if it’s expired. Instead, return it to your pharmacy.
Also, inspect the insulin before you inject it. Visual cues are helpful. Rapid-acting, long-acting, and regular insulin should be clear without floating pieces. Intermediate-acting and premixed insulin should be cloudy, but also without floating pieces or crystals. If you suspect anything funky, don’t use the insulin, and take it back to your pharmacist for concerns or a refund or exchange.
Insulin prices have been steadily increasing, making it difficult for some people without health insurance (or with limited health insurance) to afford medications. Insulin manufacturers have special programs to help lower-income individuals obtain insulin. Insulin affordability is a major advocacy issue for the American Diabetes Association.