Since there is very little fat on the forehead, the fillers must be of a certain sort. It must be sufficiently soft while still being able to plump up the treated areas without requiring excessive substance. Popular filler substances include hyaluronic acid (HA), collagen, PMMA-based fillers, and even the patient’s own fat tissues. Because of their demonstrated protection and immediate impact, HA fillers are the most widely used fillers around the world.Â