As we in the Northern Hemisphere move into summer and spend more time outdoors, it seems a good time to remind you to discard old sunscreen. You want protection, and old sunscreen won't give you that; it's just clutter.
Here's Dr. Rachel Herschenfeld, a dermatologist:
It is very important to check those expiration dates. Many sunscreen ingredients do not have an incredibly long shelf life, so throw away the old stuff and replace it!And here's Dr. Lawrence E. Gibson, a dermatologist at the Mayo Clinic:
Sunscreens are designed to remain stable and at original strength for up to three years. This means that you can use leftover sunscreen from one summer to the next.
Some sunscreens include an expiration date — the date at which time the sunscreen is no longer effective. Discard sunscreen that is past the expiration date or is more than 3 years old.
Keep in mind, however, that if you use sunscreen frequently and liberally, a bottle of sunscreen shouldn't last you that long.
[picture from drugstore.com]