Between 2010 and 2012, approximately six million Americans used either insulin alone or insulin and medication to control their diabetes, according to a 2014 CDC report. As the prevalence of diabetes increases, so does the number of people who rely on their insulin working effectively.
For people with insulin-dependent diabetes, insulin is essential, but it doesn’t do any good if it doesn’t work. If insulin is stored at incorrect temperatures, it may compromise effectiveness, leading to unpredictable blood sugar and improper dosing. A study presented at the 2018 annual meeting of the European Association for the Study of Diabetes found that a percentage of insulin users were storing their insulin at improper temperatures due to fluctuations in domestic refrigerators.
The study installed temperature sensors in the refrigerators or diabetes bags of 388 people in the United States and European Union. The sensors took measurements every three minutes, or 480 times per day. Researchers found that insulin stored in the fridge was outside the recommended storage temperature for about two hours and 34 minutes a day on average, or 11 percent of the time. Carried insulin only fell out of the recommended range for about eight minutes a day.
Let’s be honest—those numbers don’t seem that concerning. The concerning part is that people may be storing insulin incorrectly without knowing it because of fluctuating temperatures in their refrigerators. Dr. Katarina Braune, who led the study, advises people to use a thermometer to double-check their fridge temperature.
If insulin is stored at incorrect temperatures for long periods, it can impact its effect on blood glucose. Dr. Braune says, “Even gradual loss of potency introduces unnecessary variability in dosing.”
More research is needed to examine to what extent storage temperatures impact insulin efficacy. Insulin should be stored in the refrigerator at 36 to 46 degrees Fahrenheit (2 to 8 degrees celsius). Insulin in a pen, pump, or vial should be stored between 36 to 86 degrees Fahrenheit (2 to 30 degrees celsius). Insulin in vials or cartridges can be stored outside the refrigerator between 59 to 86 degrees Fahrenheit (15 to 30 degrees celsius) for up to 28 days.
No insulin should be used beyond its expiration date. The FDA recommends that insulin that’s been altered or removed from the original vial should be thrown away within two weeks. Insulin loses some effectiveness when exposed to extreme temperatures, and it should be kept out of heat and direct sunlight and not used if it’s been frozen.
Stay healthy, friends!
Katie Taylor started writing in 5th grade and hasn't stopped since. Her favorite place to pen a phrase is in front of her fireplace with a cup of tea, but she's been known to write in parking lots on the backs of old receipts if necessary. She and her husband live cozily in the Pacific Northwest enjoying rainy days and Netflix.