Depending on your skin type and your skin’s needs at a particular time, a hydrating serum may be used in place of moisturizer. Those with oily or blemish-prone skin may prefer to use our Hydrating B5 Gel in place of a traditional moisturizer. However, dry skin can benefit from using a hydrating serum in addition to moisturizer for extra skin nourishing moisture. When exercising or in a hot, humid climate, a hydrating serum may be a more comfortable moisturizer option for some.