An extract of the marine algae, Sarcodiotheca, and more particularly Sarcodiotheca gaudichaudii, is described for use in cosmetic compositions. A biofermentation of Sarcodiotheca, such as for example S. gaudichaudii, is also described. This marine bioferment is useful as a skin care active ingredient for anti-aging cosmetic applications, and particularly useful when used in combination with an extracts of red algae, such as Chondrus crispus.