1) Human skin surface film lipid was obtained by swab method with ether from 75 normal individuals from the newborn to those in the seventies of both sexes.
2) Total fatty acid composition was analysed by gas chromatography on a polyester column.
3) Variations of composition of fatty acids according to sex, age and parts of the body were analysed.
4) Regional differences: -16.00 (palmitic and branched-chain unsaturated C16) and 18.00 (stearic and branched-chain unsaturated C18) acids were higher; 14.00 (myristic) and 16.50 (palmitoleic) acids were lower on the lower extremities than on the other parts of the body.
5) Variations by sex. In adults, the male had a higher 16.50 (palmitoleic) acid content, and in adults above 50 years of age, the female had higher 18.00 (stearic and branched-chain unsaturated C18) acid content.
6) Variations by age. 14.00 (myristic) and 16.50 (palmitoleic) acids showed changes parallel to the amount of skin surface lipid with some exceptions: they were lower in childhood, and higher after adolescence. The percentages of 18.00 (stearic and branched-chain unsaturated C18) and 18.44 (oleic) acids showed an inverse change by age: they were high in childhood.
7) These changes of fatty acid composition of skin surface film lipid can be partly explained, at least, by considering them as the result of a different mixture ratio of lipids from epidermal and sebaceous gland origin.
8) It was deduced that myristic and palmitoleic acids mainly originate from the sebaceous gland and oleic acid from the epidermal cells.