WHAT FILLERS AREFillers are gel-consistency, and are injected into the skin or connective tissue, restoring hydration and volume that have been lost due to normal aging. The injectables literally “fill” volume deficits, creases and wrinkles. There are two different types of fillers: biodegradable fillers, such as collagen or hyaluronic acid, and non-biodegradable ones. Biodegradable fillers gradually degrade by the skin tissue and eventually get resorbed. Smoothline only uses biodegradable fillers, as they have shown satisfying results while being safer than non-biodegradable compounds.