Look at the packaging of your hand sanitizer. You should see an expiration date, typically printed on the top or back.

Since hand sanitizer is regulated by the Food and Drug Administration (FDA), it’s required by law to have an expiration date and lot number.

This expiration date indicates the amount of time that testing has confirmed the sanitizer’s active ingredients are stable and effective.

Typically, the industry standard is 2 to 3 years before hand sanitizer expires.

Sanitizer past its expiration date may still have some effectiveness, though, because it still contains alcohol, the active ingredient.

Even if its concentration has dropped below its original percentage, the product — although less effective, or perhaps ineffective — isn’t dangerous to use.

While hand sanitizer may still work after it’s expired, your best bet is to replace it once it’s reached its expiration date, since it may be less effective.

What active ingredients are found in hand sanitizer?

The active sterilizing ingredients in most hand sanitizers — gel and foam — are ethyl alcohol and isopropyl alcohol.

The Centers for Disease Control and Prevention (CDC) recommends using hand sanitizers that contain a minimum of 60 percent alcohol. The higher the percentage of alcohol, the more effective the hand sanitizer is at getting rid of bacteria and viruses.

Learn how to make your own hand sanitizer at home.

Hand sanitizer’s active ingredient, alcohol, is a volatile liquid that evaporates quickly when exposed to air.

Although common hand sanitizer containers protect the alcohol from the air, they’re not airtight, so evaporation can occur.

As the alcohol evaporates over time, the percentage of your hand sanitizer’s active ingredient drops, making it less effective.

The manufacturer estimates how long it’ll take for the percentage of the active ingredient to drop below 90 percent of the percentage stated on the label. That time estimate becomes the expiration date.

According to Rush University, hand sanitizers haven’t been shown to offer any greater disinfecting power than washing your hands with soap and water.

The university suggests that washing with soap and warm water is a better choice than using hand sanitizers in most cases.

The CDC recommends that you frequently wash your hands with soap and water to reduce germs and chemicals on your hands. But if soap and water aren’t available, hand sanitizer is OK to use.

According to the CDC, washing with soap and water is more effective for removing germs, such as Clostridium difficile, Cryptosporidium, and norovirus.

The CDC also reports that alcohol-based hand sanitizers aren’t as effective if your hands are visibly dirty or greasy. They may also not remove harmful chemicals, such as heavy metals and pesticides, but handwashing can.

The CDC suggests a three-step method for using hand sanitizer:

  1. Check the hand sanitizer label for the correct dosage, then put that amount in the palm of one hand.
  2. Rub your hands together.
  3. Then rub the sanitizer over all surfaces of your fingers and hands until they’re dry. This usually takes about 20 seconds. Don’t wipe or rinse off the hand sanitizer before it’s dry.

Hand sanitizer has an expiration date that indicates when the percentage of active ingredients drops below 90 percent of the percentage stated on the label.

Typically, the industry standard for when hand sanitizer expires is 2 to 3 years.

While not dangerous to use hand sanitizer after its expiration date, it may be less effective or not effective at all. When possible, it’s best to wash your hands with soap and water. If that’s not possible, using nonexpired hand sanitizer is your best bet.