As summer starts to wind down temperatures become less blistering, pools become less crowded and that giant bottle of sunscreen sputters as families try to eke out the dregs of liquid sun protection from inside. No one wants to have to buy a new bottle of sunblock at the end of the season.
But sun protection is important. So what about using the leftovers of last year’s bottle, the one hiding in the bottom of the swim bag or under the seat of the car? Is it worth it to save the precious potion from year to year?
According to Dr. Lawrence Gibson of the Mayo Clinic, it is.
“Sunscreens are designed to remain stable and at original strength for up to three years,” he said in an article on MayoClinic.com. “This means that you can use leftover sunscreen from one year to the next."
Dr. Henry Lim and Dr. Steven Wang of the Skin Cancer Foundation have come to a similiar conclusion.
“There is no need to throw away last year's left-over sunscreens,” they advise in this article on the Skin Cancer Foundation's website. “Shelf life is typically two to three years.”
Many sunscreens have expiration dates stamped on their sides to help consumers know when they should be discarded. A quick glance at the bottle will likely tell if the lotion is still good.
But, if parents are unsure how long that bottle has been buried in the back of the cabinet, they don’t have to just toss it in the trash.
“If there is no expiration date, you can always call the customer service number listed on the label,” cancer educator Lisa Fayed said in an article on cancer.about.com. “You can provide them with the codes that are printed on the bottle and they can tell you if it has expired.”
And what about that sunscreen that loitered around in the car all summer? According to Gibson, you might want to toss that bottle out. "Discard sunscreen that's past the expiration date, is more than three years old or has been exposed to high temperatures," he said.
Gibson also warns that proper use of sunscreen will make leftovers much less likely as a liberal application is about an ounce. And with simple math, if it's a four-ounce bottle, then a fourth of it will be used at a time.
Melissa DeMoux is a stay-at-home mother of six young children who lives in West Valley City, Utah. Her email is email@example.com and she blogs about her adventures in motherhood at demouxfamily.blogspot.com.