Every day, millions of Americans get prescription medications delivered to their homes. It’s a convenient option, but rising temperatures can make safe transport challenging and put the drugs at risk.

Temperature and humidity levels can affect drugs all year round, but the likelihood of a problem is highest during the summer. Whether you are enrolled in a mail-order pharmacy program or are ordering over-the-counter pills from Amazon, it’s important to consider how compounds could be affected on their way to your doorstep.

Are my medications really being exposed to extreme heat?

For many oral medications, the United States Pharmacopeia, an independent organization that sets standards for the nation’s drug supply, recommends keeping medications at temperatures of 68 to 77 degrees Fahrenheit. It allows for an expanded temperature range of 59 to 86 degrees to accommodate for mild “excursions,” as long as the average temperature does not exceed 77 degrees.

Most mail-order pharmacies say that their packaging is weather resistant. But research has shown that packages sometimes spend more than two-thirds of transit time outside the appropriate temperature range.