3-Aminopropyl dihydrogen phosphate (3-APPA; 3-aminopropane phosphoric acid) was developed by novel synthetic procedure, and its applicability to the skin as a cosmetic raw material was examined in terms of the efficacy. We have measured the effect of 3-APPA not only on the growth of fibroblast and the collagen synthesis in normal human dermal fibroblast cultures, but also on the skin of hairless mice. The addition of 3-APPA (0.1 to 10 μg/ml) in culture system containing DMEM with 10% FBS showed about 2-fold increasing of fibroblast proliferation, as measured by MTT assay. Similar concentration of 3-APPA increased collagen synthesis in monolayer culture system and three-dimensional culture system(collagen gel matrix), as measured by 3 H-proline incorporation methods. The expression of alpha 1(I) procollagen mRNA was correlated with the above results. For the in vivo analysis, hairless mice were treated with 10% 3-APPA daily for 3 weeks. By histological observation, the increased synthesis of collagen was shown. We conclude that 3-APPA has a anti-aging effect according to enhancing the proliferation and increasing the expression of collagen in vitro and in vivo studies.