极低密度脂蛋白为一种由肝脏制造的脂蛋白。极低密度脂蛋白为五种主要的脂蛋白中的其中一种(乳糜微粒、低密度脂蛋白、中密度脂蛋白、高密度脂蛋白、VLDL)，可以使脂肪和胆固醇在水溶性的血液中移动。VLDL在肝脏中由三酸甘油脂、胆固醇、和载脂蛋白组成，极低密度脂蛋白在血液中转换成低密度脂蛋白。极低密度脂蛋白粒子直径为30~80 nm。极低密度脂蛋白运送内源性物质，然而乳糜微粒发送饮食进来的物质。近年来，脂蛋白脂质的组成和蛋白质的组成的特色都已有渐渐了解了。

Very-low-density lipoprotein (VLDL) is a type of lipoprotein made by the liver. VLDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, low-density lipoprotein, intermediate-density lipoprotein, high-density lipoprotein) that enable fats and cholesterol to move within the water-based solution of the bloodstream. VLDL is assembled in the liver from triglycerides, cholesterol, and apolipoproteins. VLDL is converted in the bloodstream to low-density lipoprotein (LDL). VLDL particles have a diameter of 30-80 nm. VLDL transports endogenous products, whereas chylomicrons transport exogenous (dietary) products. Recently both the lipid composition and protein composition of this lipoprotein were characterised in great detail.