If it's not congenital gray hair, or hereditary gray hair, it's gray hair caused by acquired malnutrition and mental stress. Of course, it refers to healthy gray hair. If it's acquired pathological gray hair or chemotherapy gray hair, there's no way to change it forever. You will see a certain improvement if you drink about 5 cans of Ruliduo Blackhair Powder normally. Of course, it's a long-term process to turn gray hair into black hair, so you have to stick to it.