Cross Linker in Ha Fillers (Juvederm/Restylane)?

 Dr Rueckl has done a good job of explaining cross linking in simple terms. The process turns HA from a viscous liquid to a gel of different degrees of thickness. The more cross linking, the thicker the gel and typically the longer it lasts. There is no by product as it breaks down. It just degrades slower.

HA fillers like Juvederm and Restylane are "cross linked". In hyaluronic acid’s natural form, the substance is a liquid which the body metabolizes in about half a day. Cross linking is a process that chemically binds the individual chains of the acid so that it is changed into a gel that lasts much longer once injected inside facial tissue. Some scientists believe the higher cross linked (more tightly bound) a filler is, the longer it has the potential to last in the body; though other scientists disagree about this. Over time, the gel that the HA now is in the injectable "filler" state, will break down and metabolize within the body. Nothing is left behind as a byproduct.