PCL was approved by the FDA for specific applications used in the human body as drug delivery devices and sutures.  PCL is now widely being used following the recent introduction of a PCL-based microsphere dermal filler belonging to the collagen stimulator class and throughout Asia with the development of PCL cosmetic threads.  Through the stimulation and production of type 1 and 3 collagen, PCL threads are able to correct facial aging signs such as volume loss and contour laxity, providing an immediate and long-lasting natural effect. Biodegradation of PCL occurs through a process of hydrolysis over a time period of between 18 to 24 months while the aesthetic duration of threading results has been found to last between two to four years. PCL threads are softer than PDO and PLLA and they last longer than any other cosmetic thread.