Method of cosmetic treatment of sagging skin comprises applying at least one polymer to the skin, where: the polymer is obtained from the polymerization reaction of a tensing agent precursor (i) having at least one aryl ring with at least two hydroxyl groups carried by two consecutive carbon atoms of the aromatic ring； and the polymerization reaction is carried out by contacting the precursor tensor agent (i), in the presence oxygen, with a catalyst system comprising e.g. first component (ii) comprising salts and oxides of manganese(II) (Mn(II)) and/or zinc(II) (Zn(II)). Method of cosmetic treatment of sagging skin comprises applying at least one polymer to the skin, where: the polymer is obtained from the polymerization reaction of a tensing agent precursor (i) having at least one aryl ring with at least two hydroxyl groups carried by two consecutive carbon atoms of the aromatic ring； the polymerization reaction is carried out by contacting the precursor tensor agent (i), in the presence oxygen, with a catalyst system comprising a first component (ii) comprising salts and oxides of manganese(II) (Mn(II)) and/or zinc(II) (Zn(II)), and a second component (iii) comprising alkali metal hydrogen carbonates and/or alkaline earth metal hydrogen carbonates； and (i), (ii) and (iii) are included in a three distinct cosmetic composition before contacting. An independent claim is included for packaging set comprising at least: (i) an extract from maritime pine bark containing 60 wt.% of procyanidins, (ii) a first component of a catalyst system comprising salts and oxides of Mn(II) and/or Zn (II), and (iii) a second component of a catalyst system comprising alkaline earth metal hydrogenocarbonates, where the packaging set is in the form of: either as a single compartment devoid of oxygen which are simultaneously at least the compounds (i), (ii) and (iii)； or a kit consisting of at least two separate containers, in which the compounds (i), (ii) and (iii) are not present simultan
