Terpinen-4-ol is an isomer of terpineol with the chemical formula CHO. Total synthesis of complex natural compounds increased in complexity to glucose and terpineol. The constituents include phellandrene, limonene, elemol, elemicin, terpineol, carvone, and terpinolene. Terpineol is usually a mixture of these isomers with "alpha"-terpineol as the major constituent. Although it is naturally occurring, terpineol is commonly manufactured from the more readily available alpha-pinene.