We’ve all tried to figure out how to get rid of dark circles under eyes. Something not even a good night’s sleep or high-coverage concealer can always make disappear. But did you know there’s a really easy thing you can do right now to see which type of treatment could banish them for good?

Madi Prettyman, the beauty TikToker behind the account @chooseyourglow, shared a skincare hack that will teach you how to get rid of dark circles under eyes in record time. And what is this amazing hack, you ask? The “pinch test”—something Dr. Dennis Gross, the famed board-certified dermatologist behind the skincare line of the same name, originally came up with.

According to Pettyman, the process is simple: “Slightly pull the under-eyes up a little bit to see if the darkness disappears or not,” she says. That small move is telling of what your next step should be.

“If [the darkness disappears], that means your skin is thin and the purple veins are showing through. So you want something to help with building collagen, like vitamin C,” she says “If the color stays, that means your skin is discolored and you’ll want an ingredient like retinol to help resurface or brighten the skin.”

This hack is so easy that it probably seems too good to be true. But aside from Dr. Gross, it’s a quick trick Amy Michaels Koberling, PA-C, the board certified physician assistant behind the account @the_skinthusiast, uses as well.

“This is something I do at my clinic to determine the cause of my patients’ dark circles,” Koberling says in a video. “If the darkness is caused by vessels underneath, look for vasoconstrictors like caffeine and ingredients to build collagen. If the skin itself is pigmented, look for brightening ingredients—and yes, retinoids.”

Who knew finding the real cause behind those pesky dark circles could be so simple? After using the hack to figure out which ingredient is best for you, grab the sustainable beauty products below.

Try the Hack, Then Remove Dark Circles Under Eyes

For Vitamin C: Cocokind Vitamin C Serum, $18

If the darkness disappears when you gently pull your under-eyes up a bit, try using a vitamin C serum like this option from Cocokind. As a refresher, “That means your skin is thin and the purple veins are showing through. So you want something to help with building collagen, like vitamin C,” says Prettyman.

For Retinol: Alpyn Beauty PlantGenius Line-Filling Eye Balm, $62

If the color stays when you gently pull up your under-eye area, “that means your skin is discolored and you’ll want an ingredient like retinol to help resurface or brighten the skin,” says Pettyman. Try this option from Alpyn Beauty that’s made with wildcrafted and hand-cultivated botanicals.

Beauty, Clean Beauty, Skincare