Serums and moisturizers are two different types of skin care formulations, and the key distinctions are when they are applied and that a serum can deliver additional benefits. Serums should be applied before lotion or cream, or they can be used in place of a moisturizer if the serum is formulated with hydrating ingredients. Our Hydrating B5 Gel serum can play the role of both since it provides the skin with essential moisture on its own; however, those with drier skin may choose to layer it beneath a hydrating lotion or cream. In many cases, a serum contains ingredients that target a particular skin concern.