Abstract: The invention concerns a complex comprising at least a lipid and at least a therapeutically active substance useful for transferring said substance into a target cell, characterised in that said lipid is of formula (I): in which: n1, n2, identical or different are whole numbers between 0 and 1; R1, R2, identical or different are: a) selected among the group consisting of a hydrogen atom and alkyl radicals with 1 to 6 carbon atoms optionally substituted, independently of one another, by a hydroxyl radical; or b) in one particular case for which n1=n2=1, R1 and R2 can form together a divalent alkylene chain of 2 to 3 carbon atoms (C2-C3); R3, R4, identical or different are alkyl radicals of 1 to 6 carbon atoms or can together form a divalent alkylene chain of 2 to 3 carbon atoms (C2-C3); m, p, identical or different are whole numbers between 1 and 10; R5, R6, identical or different are selected in the group consisting of radicals of formula: 1) R7 C(═O)—X— in which: X=NH, O