SkinMedica HA5 Rejuvenating Hydrator is a hydrator that works to support moisture in the skin. Unlike other hyaluronic acid (HA) serums that only temporarily moisturize the surface, HA5 has 5 different forms of HA that work synergistically to provide instant smoothing results and continuous hydration throughout the day. HA5 hydrates your skin. Well–hydrated skin is smooth, soft, and healthy looking, with fewer visible lines and wrinkles.