Cosmetic composition

A synthetic pseudoceramide having the structure (2):

• ##STR13## where R represents a linear or branched, saturated or unsaturated, hydroxylated or non-hydroxylated, phosphorylated or non-phosphorylated, sulphated or non-sulphated aliphatic hydrocarbon group having from 1 to 49 carbon atoms or the sub-group Y--O--(C.sub.a H.sub.b)--;
• R.sup.1 represents a linear or branched, saturated or unsaturated, hydroxylated or non-hydroxylated, phosphorylated or non-phosphorylated, sulphated or non-sulphated aliphatic hydrocarbon group having from 1 to 28 carbon atoms;
• R.sup.2 represents H, a sugar residue, a sulphate residue or a phosphate residue P.sub.i ;
• P.sub.i represents the group:
• ##STR14## R.sup.3 represents H, or the sub group (3):
• ##STR15## X.sup.1, X.sup.2 and X.sup.3 each individually represent H C.sub.1-5 alkyl or C.sub.1-5 hydroxyalkyl;
• Y represents H or a residue or a C.sub.14-22 fatty acid having the structure (4):
• ##STR16## Z represents --OH --OP.sub.i, --OSO.sub.3 or an epoxy oxygen, a is an integer of from 7 to 49
• b is an integer of from 10 to 98
• c is 0 or an integer of from 1 to 4
• d is 0 or 1
• x is an integer of from 12 to 20
• y is an integer of from 20 to 40
• z is 0 or an integer of from 1 to 4
• n is 0 or 1
• m is 1.