The present invention relates to the modification of hyaluronic acid (HA) witharyl/alkyl succinic anhydrides (ASA) to produce aryl/alkyl succinic anhydrideHA derivatives, to the derivatives as such, and to their applications anduses, particularly in the cosmetic and biomedical industries. The ASA-HAderivatives are expected to have interesting properties that can be used foradvanced formulation (bind stronger to the skin compared to non-modified HA),possibly also in delivery systems for actives or drugs by encapsulation(nano/micro capsules) or formation of nano/micro spheres. Further, the low MWASA-HA derivatives are expected to penetrate the skin more efficiently thannon-modified HA of the same MW.