Fat is a very common material used as a filling substance in facial rejuvenation. The fat that we inject into facial areas comes from your own body, so there is no chance of an allergic reaction. Fat can be used in higher volumes than most other injectable materials and can be used to create a fuller, more youthful appearance by reestablishing pleasing contours. Injections of fat into the deep layers of facial tissue can soften the angular, thin appearance that often accompanies aging. The procedure is a two-step process that usually requires several treatments. The fat must be harvested from your own body, typically from the abdomen, thighs or hips.