Behold: The 50 Best Skin-Care Products of 2021, According to Editors

If it ain't broke, why fix it? That's what you might think about Drunk Elephant's bestselling vitamin C serum, but the brand's new C-Firma Fresh Day Serum ($78) was created with a longer shelf life in mind. It uses the same blend of potent ingredients you'd find in the original, only you choose when you're ready to use it by mixing one bottle's ingredients with the other's.

"By separating the formula of C-Firma into two phases, one phase being the liquid serum base and other being the active vitamin C, the user is able to choose the moment of 'activation' for their C-Firma Fresh, which happens when they mix the two phases together," founder Tiffany Masterson told POPSUGAR. "That means no more color shifts and no wondering how much time your C-Firma will remain at its most potent."