Many different factors contribute to acne, and one of the main ones involves changes in the skin’s natural oils (known as skin surface lipids, or SSL). These changes don’t just relate to the amount of lipids produced by the skin, but also the composition (i.e. content) of the lipids produced, right down to a molecular level. In this study, scientists analysed SSL in 35 people with acne and 35 without. 874 lipids were identified and each was classified into one of eight main classes, and these main classes were further broken down into sub-classes or species. The researchers then looked at the amount of each main lipid class present in the different patients. The scientists discovered obvious variations of SSL composition, not just between different skin states (e.g. acne or no acne) but also between males and females. People with acne were found to have increased levels of 3 main classes (called fatty acyls, glycerophospholipids and sterol lipids) and decreased levels of 2 main classes (prenol lipids and saccharolipids), whereas there was no significant change of the relative amount of the other 3 main classes (glycerolipids, sphingolipids and polyketides). 36 individual lipid species were the most important entities responsible for the differences between SSL from young men with acne and from people without acne. It is hoped that better understanding these changes may help to pave the way for new, targeted acne treatments in the future.