Abstract: The invention concerns novel lipid compounds suitable for the transport of biologically active substances or molecules in cells. A preferred compound according to the invention is L-lysine-bis-(O,O′-cis-9-octadecenoyl-&bgr;-hydroxyethyl)-amide dihydrochloride or one of its optical isomers. In addition, the invention concerns complexes of the novel lipid compounds with polyanions such as DNA and RNA, and ternary complexes of the novel lipid compounds with polyanion and polycations. Finally, the invention concerns liposome formulations made from biologically active substances and the novel lipid compounds, as well as methods of transporting polyanions, polycations or biologically active substances through biological membranes by means fo the novel lipid compounds.