According to the search results, moisturizer should be applied before primer. Moisturizer is meant to hydrate the skin and lock in moisture to keep dryness at bay, while primers are not formulated to provide skin with moisture. Applying primer before moisturizer can lead to dry, lackluster skin. It is important to apply moisturizer first to ensure that the skin receives the full benefits of the product. Once you have picked a moisturizer, it should be used twice a day: in the morning before your sunscreen and at night before bed. Primer should be applied once a day, just before your makeup.