We put it to the test. Viral beauty products are a funny thing. Some of them are a flash in the pan, getting their 15 minutes ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." My fellow editors and I put Kosas' bestselling products to the test, and let me tell you, they delivered.

All linked products are independently selected by our editors. If you purchase any of these products, we may earn a commission. If you were to take a look inside any beauty editor’s makeup bag, you'll ...