Highly concentrated in pure Hyaluronic acid, which is naturally present in the skin and is capable of attracting up to 1000 times its weight in water, this nightly cream penetrates the heart of the epidermis to re-infuse the skin with moisture and restore comfort. AQUA PLUS Sleeping Mask contains Hyaluronic acids of three different molecular weights: The highest molecular weight acts as a "protective coat". Its surface action is immediate and helps prevent water loss. Particles fragmented in medium and low molecular weights deeply penetrate all the epidermis layers to replenish skin with moisture.