Does it matter if I use an essence v serum? The answer is yes, ideally, you'll want to use both. If you only have time or patience to apply one, look at your overall skincare routine to decide which one you'll keep. Essences are lighter and help bind your moisturizer to your skin. Serums are generally a little thicker and while they perform similarly to essences, they can help address skin concerns such as dark spots or brightening your skin. Looking for that unicorn essence or serum to help your skin, try a couple of different ones and see which one your skin likes.