This invention provides an agent for the improvement of wrinkle formation as a cosmetic material, which has a novel core structure and is useful in the components of an agent for external use on skin. The agent for the improvement of wrinkle formation comprises a compound of formula (1), an isomer thereof, or a pharmaceutically acceptable slat thereof； and the said agent has excellent effects on improving the wrinkle formation and loosen skin caused by skin-aging as one ages or by photo-aging from UV radiation.wherein R1is hydrogen, or straight or branched-chain C1~C8 alkyl； R2is -SH, -SO3H, -S-S-X1, -S-X2, -SO-X3, -SO2-X4, -SO2-NY1-X5, or -SO2-NY2-Y3； X1~X5are indenpently hydrogen, or C1~C8 aliphatic hydrocarbon group or C5~C12 aromatic part in which the carbon atom is optionally substituted by hetro atoms； Y1~Y3are indenpently hydrogen, or straight or branched-chain C1~C8 alkyl； R3is hydrogen, or acyl group having straight or branched-chain C1~C8 alkyl； R4is unsubstituted or substituted C5~C12 aromatic group or multicyclic-fused aromatic group； m is an integral of 0 to 3； and n is an integral of 1 or 2.本發明課題是提供適宜作為化妝材料等之皮膚外用劑成分之具有新穎母核的皺紋改善劑。經由含有下記一般式(1)表示之化合物、其立體異構物、或彼等之藥理學上容許的鹽之皺紋改善劑來解決課題。該皺紋改善劑對於年齡增加所伴隨之皮膚老化以及因暴露於紫外線之光老化所產生之皺紋、鬆弛等具有優異的改善效果。[式中，R1表示氫原子、或碳原子數1~8之直鏈或分枝之烷基；R2表示-SH、-SO3H、-S-S-X1、-S-X2、-SO-X3、-SO2-X4、-SO2-NY1-X5、或-SO2-NY2-Y3，前記X1~X5獨立地為氫原子或碳原子可經雜原子取代之碳原子數1~8之脂肪族烴基或碳原子數5~12之芳香族部分，前記Y1~Y3獨立地表示氫原子、或碳原子數1~8之直鏈或分枝之烷基；R3表示氫原子、或具有碳原子數1~8之直鏈或分枝之烷基鏈的醯基；R4表示無取代或可具有取代基之碳原子數5~12之芳香族基或多環稠合芳香族基；m表示0~3的整數；n表示1或2的整數。]
