Efficacy

In RESTYLANE™, the overall NASHA gel concentration is 20 mg/ml stabilized HA. This concentration has been carefully selected to provide optimal maintenance of volume for tissue augmentation and lifting. An important advantage of the non-animal stabilized hyaluronic acid used in other related products is its prolonged residence time in the tissues. However, NASHA, like other biodegradable implants, is slowly broken down after injection. With conventional biodegradable implants, this has the disadvantage that the implant progressively shrinks and the esthetic benefit therefore quickly diminishes. Uniquely, with NASHA products the slow biodegradation of the stabilized HA does not lead to gradual shrinkage. As the NASHA is degraded, each molecule progressivly binds more water, more free water binding sites per molecule. This process is called isovolemic degradation. Thus, with the implants, volume is maintained until the stabilized gel is almost completely degraded. When the gel is completely degraded, the remaining HA fragments are metabolized together with the natural tissue HA, and no trace of the original implant remains.