Polyaminoacids (I) comprising glutamic units comprising histidine derivatives and hydrophobic groups that are optionally identical with the histidine derivatives, are new. Independent claims are included for: (1) a cosmetic, dietary or phytosanitary composition comprising the polyglutamate modified by a histidine derivative; (2) a composition comprising the polyaminoacid; and (3) a preparation of drugs comprising applying the polyaminoacid and/or the composition to an active principle.