Abstract: The invention relates to peptide derivatives (peptides and pseudo-peptides) and the use thereof as vectors for molecules of interest. The invention also relates to conjugates containing a peptide derivative of the invention bound to a molecule of interest. The peptides of the invention can be used, in particular, to vectorize, generally in the form of prodrug conjugates, molecules of pharmaceutical or diagnostic interest such as, for example, therapeutic molecules, imaging or diagnostic agents, or molecular probes, across cell membranes of different tissues or organs, healthy or pathologic, and in particular to enable their transport across physiological barriers of the nervous system such as the Blood brain barrier (BBB), Blood-spinal cord barrier (BSCB), or Blood-retinal barrier (BRB).