A peptide conjugate of formula below: R 1 -X 1 -X 2 -X 3 -X 4 -A 1 -R 2 wherein: - R 1, which is on the N-terminal side, is a hydrogen atom, or a fatty chain chosen from a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl group, a substituted or unsubstituted, linear or branched C 21 -C 50 alkylaryl group, a substituted or unsubstituted, linear or branched C 13 -C 50 alkenyl group, or an R 3 -CO-, R 3 -OCO- or R 3 -COO- group wherein R 3 is a substituted or unsubstituted, linear or branched C 13 -C 49 alkyl or alkenyl group, the substitutions including F, Cl, or any lipophilic heteroatom or heteroatom group such as a guanidine or a guanidinium; - X 1 is an -serine condensate, - X 2 is an - and/or -aspartic acid condensate, - X 3 is an - and/or -lysine condensate, - X 4 is an - and/or -proline condensate, - X 4 optionally being absent, - the bonds linking X 1 to X 2, X 2 to X 3 where appropriate, and X 3 to X 4 where appropriate, possibly being peptide or pseudopeptide bonds, - A 1 is a covalent bond, an NH group or an oxygen atom, - R 2 is a hydrogen atom, or a fatty chain chosen from a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl group, a substituted or unsubstituted, linear or branched C 21 -C 50 alkylaryl group, a substituted or unsubstituted, linear or branched C 13 -C 50 alkenyl group, or an R 4 -CO- or R 4 -OCO- group wherein R 4 is a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl or alkenyl group, the substitutions including F, Cl, or any lipophilic heteroatom or heteroatom group such as a guanidine or a guanidinium group, - R 1 and R 2 not being able to both be hydrogen atoms, or a pharmaceutically acceptable salt thereof. - R 1, which is on the N-terminal side, is a hydrogen atom, or a fatty chain chosen from a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl group, a substituted or unsubstituted, linear or branched C 21 -C 50 alkylaryl group, a substituted or unsubstituted, linear or branched C 13 -C 50 alkenyl group, or an R 3 -CO-, R 3 -OCO- or R 3 -COO- group wherein R 3 is a substituted or unsubstituted, linear or branched C 13 -C 49 alkyl or alkenyl group, the substitutions including F, Cl, or any lipophilic heteroatom or heteroatom group such as a guanidine or a guanidinium; - X 1 is an -serine condensate, - X 2 is an - and/or -aspartic acid condensate, - X 3 is an - and/or -lysine condensate, - X 4 is an - and/or -proline condensate, - X 4 optionally being absent, - the bonds linking X 1 to X 2, X 2 to X 3 where appropriate, and X 3 to X 4 where appropriate, possibly being peptide or pseudopeptide bonds, - A 1 is a covalent bond, an NH group or an oxygen atom, - R 2 is a hydrogen atom, or a fatty chain chosen from a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl group, a substituted or unsubstituted, linear or branched C 21 -C 50 alkylaryl group, a substituted or unsubstituted, linear or branched C 13 -C 50 alkenyl group, or an R 4 -CO- or R 4 -OCO- group wherein R 4 is a substituted or unsubstituted, linear or branched C 13 -C 50 alkyl or alkenyl group, the substitutions including F, Cl, or any lipophilic heteroatom or heteroatom group such as a guanidine or a guanidinium group, - R 1 and R 2 not being able to both be hydrogen atoms,