Raise your hand to your go-to sunscreen (opens in new tab) to take to the beach or pool, your favorite spray-on SPF, your favorite scented lotion, or your go-to convenient stick for makeup application during the summer months. But as soon as fall rolls around and you start eating cider donuts, the SPF (opens in new tab) you've come to rely on is relegated to the bottom of your beach bag and basically forgotten until MDW. The next year, as I pull out my SPF, which has regained its pre-summer glow, a little question comes to mind: is this sunscreen expired?

It is of utmost importance that sunscreen is not expired and in top condition, not to mention that it must be more diligent than other cosmetic products. Expired sunscreen will not protect you from harmful UVA and UVB rays. Happily, there are some strict and quick rules to help you easily determine if your sunscreen is expired, i.e., still effective.

First of all, any product (including sunscreens) that is not clearly marked or stamped with an expiration date is required by the FDA (open in new tab) to be stable for at least three years.

I know what you are thinking. Next time you buy sunscreen (and rarely when it's not labeled with an expiration date), consider writing the date of purchase on the side with a sharpie.

Also, "If you're applying sunscreen liberally and correctly, and you're outside with a relative frequency that isn't cave dwellers, one sunscreen should last you at least three years. Most of the time, you'll be fine. If you found sunscreen at a friend's parents' beach house and admired the retro packaging, you're not good.

Thankfully, however, most sunscreens are clearly stamped, embossed, or have a sticker with the expiration date. (The FDA recommends keeping sunscreens away from direct sunlight and heat to ensure that they remain potent throughout their natural lifespan. If you are outside for long periods of time, consider bundling the sunscreen in a towel and sticking it to the back of a chair or keeping it in the air conditioner (cooler temperatures will not degrade sunscreen). Apply sunscreen, put on sunglasses and a hat, cover up, and you're ready to start sunbathing.