Neutrogena® Hydro Boost Hyaluronic Acid Concentrated Serum intensely hydrates and activates hyaluronic acid production* and provides intense moisture for smoother skin in 2 weeks**. With the highest concentration of hyaluronic acid within the Hydro Boost range, 100% natural derived trehalose and Provitamin B5. This light-weight, skin-plumping serum intensely hydrated to quench skin whilst stimulating the skins' own hyaluronic acid production*, improving skin's hydration * in-vitro study ** Scientific study with 35 participants