No, gochugaru is actually only one of the many other ingredients that made up gochujang. Gochugaru is basically the Korean version of dried chili flakes, and it is also sometimes available in the powdered form. As for gochujang, it is not just only made from gochugaru, but also other ingredients like fermented soy beans, glutinous rice and other seasonings. It also has a thick, tomato paste kind of texture. Hence, I will not recommend using gochugaru as a substitute for gochujang.