NZ 603805 Disclosed is the use of a composition for producing a non-totipotent stem cell population comprising a lipopeptide of the formula as disclosed in the abstract drawing wherein, R1 represents H or -CO-R4, R2, R3 and R4 independently are H or optionally substituted C6-C20 aliphatic, X is a peptide selected from the group consisting of SEQ ID NOS: 8, 16-18, 20, and 21 disclosed in the specification, and Z is S or CH2; and wherein the non-totipotent stem cell population is not produced in a human.