At least one cyclic peptide is used as an active component in a non-therapeutic cosmetic treatment of the skin and/or its appendages, said cyclic peptide consisting of at least five amino acids including at least one proline (Pro) and at least one two phenylalanine (Phe), the other amino acids being chosen from the group comprising leucine (Leu), isoleucine (Ile), valine (Val), alanine (Ala), glycine (Gly), methionine (Met) and tryptophan (Trp), methionine (Met), when present, may be unoxidized or oxidized. Preferably, said at least one cyclic peptide is a mixture of cyclic peptides extracted from flax seed oil. The cosmetic treatment is particularly effective for firming skin and more particularly in combination with an extract of seeds of Apium graveolens effective on the pores for a smooth and satiny rendering of the skin.
