Shiseido developed sodium acetyl hyaluronate (AcHA), through partial substitution of hydroxyl groups of sodium hyaluronate (HA) by acetyl groups. The treatment let the sodium hyaluronate possess hydrophobicity in addition to the original hydrophilic nature. The new compound showed remarkably increased affinity to the skin surface and water holding capacity("anchoring humectant"). The high water holding capacity and corneum softening effect brought by the "anchoring" effect are the advantages of sodium acetyl hyaluronate.