Collagen Stimulators based on poly-L-lactic acid are designed to stimulate the production of new tissue in the body. When a foreign substance is injected into the buttocks the body seeks to repair the damage and encapsulate the substance which creates the additional volume in the form of type III collagen.
Adjustable / Safety
A downside of using poly-L-lactic acid is the inability to dissolve or alter the result if something goes wrong, or needs to be adjusted.
Poly-L-lactic acid is a form of plastic and once it is injected into the body it can not be altered.
The patient must wait for the substance to break down on its own.
With Hyaluronic acid filler, the result can be altered following the procedure, if necessary, with the injection of Hyaluronidase enzyme.
Volume / Cost
To achieve the same results as with Hyaluronic acid, a patient would need to spend considerably more money if using injectable poly-L-lactic acid collagen stimulator. On the plus side, the filler will last a little longer than Hyaluronic acid (typically 2 years, versus Hyaluronic acid 9-18 months).
Method of Injection
It is important to inject either of the fillers using a cannula, rather than the needle supplied with the filler (which in the case of the collagen stimulator is only designed for injection in the face). A cannula will allow the filler to be injected deeper into the correct layer of tissue, which improves the result and lowers the risk of any lumps forming.