Interleukin-1 alpha (IL-1α) is a non-secreted proinflammatory cytokine produced mainly by activated macrophages, as well as neutrophils, epithelial cells, and endothelial cells. It possesses metabolic, physiological, haematopoietic activities, and plays one of the central roles in the regulation of the immune responses. Both IL-1α and IL-1β binds to the same receptor and has similar identical biological properties. Among various species, the amino acid sequence of mature IL-1α is conserved 60 % to 70 % and human IL-1 has been found to be biologically active on murine cell lines. IL-1α recently started to find effective application in cosmetic and dermatological formulations, which allow to significantly harmonizing derma architecture.