Yes, heat can make many medications less effective, and in some cases, it can even make them dangerous. Exposing your medications to high temperatures can cause them to break down and lose their potency in a matter of hours, days, or weeks.

Most shelf-stable medications — like over-the-counter pills, capsules, and powders — are designed to be kept at room temperature. For most drugs, “room temperature” means between 59°F and 86°F (15°C to 30°C).

Liquid solutions and biologic injections are even more sensitive to temperature changes. It’s common to keep essential medications like insulin, naloxone (Narcan), or EpiPens in a purse or in the car for portability. But leaving them in a hot car and fluctuating temperatures during the summer can rapidly degrade them.

To keep your medicine safe and effective, be mindful of where you store it:

  • On the go: Never leave medications in a parked car, trunk, or glove box. If you’re traveling in the heat, carry temperature-sensitive drugs in an insulated cooler bag. However, make sure the medication doesn’t directly touch the ice packs, because freezing can also damage them.
  • At home: Avoid storing medications in the bathroom medicine cabinet, as showers create both heat and humidity. Keep them away from sunny windowsills or cabinets directly above the stove. Instead, opt for a cool, dry place like a bedroom drawer or closet.
Medical Perspective

What is the safest, most practical way to carry temperature-sensitive emergency meds outside of the home without accidentally freezing them on an ice pack?

“Keep your medications wrapped in cloth so they never touch the ice directly, or use a special cooling pouch that chills without freezing. Store your medications in the middle of your bag, not right against the cold pack, and avoid direct ice contact since freezing can damage it.”

— Alex Nguyen, PharmD, RPh, CPh

» Learn more: Essential Tips for Traveling with Medication

Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

It can be hard to tell if heat has damaged a medication, but there are a few physical signs to look out for. Pills or capsules might stick together, chip, crack, or change color or smell. Creams may separate, and liquids or injections might look cloudy, discolored, or develop crystals.

Never take a medication if it looks different than expected, even if it hasn’t reached its expiration date. Improper storage can make medications expire more quickly.

If you suspect your medication has been damaged by heat, consult a pharmacist for a replacement, or learn more about how to safely dispose of unused medications.

Your pharmacist is also a great resource for tips and guidance on how to store your specific medications.

Disclaimer: While Healthline strives for factual, comprehensive, and current information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.