Collagen, human collagen, and fat: the search for a three-dimensional soft tissue filler.

As the body ages, not only are the soft tissues of the face subject to gravity but they also may undergo progressive atrophy. Suspensory procedures may return the tissues to a more youthful position, but the atrophic changes are left uncorrected and produce an aged appearance. Three-dimensional (3-D) soft tissue fillers ideally would replace the bulk that was lost. Safety, persistence, and verisimilitude to the native tissues should be optimal in useful 3-D fillers. To date, no such material has been described, but there has been a resurgence in natural materials for this purpose. This article serves as an update on human-derived soft tissue fillers.