Animal-based hyaluronic acid fillers: Scientific and technical considerations

Background: Successful clinical application of dermal filler products requires an understanding of their physical characteristics and in vivo behavior. This study reviewed the data for hyaluronic acid dermal filler products derived from an animal source-the rooster comb. Methods: A review of the hyaluronic acid literature was performed. Clinical experience with the animal-derived hyaluronic acid products was evaluated. Results: The source of the hyaluronic acid has not been demonstrated to be a clinically important point of differentiation among filler products. Hypersensitivity reactions are rare and are also present in the products derived from bacteria. Variations that effect the hyaluronic acid products' physical characteristics and clinical performance are more closely related to cross-linking and formulation. Hyaluronic acid gel derived from animal sources is cross-linked by a sulfonyl-bis-ethyl bond and is a soft gel compared with other hyaluronic acid products. There is minimal gel swelling, which results in modest postinjection edema. Optimal clinical application favors patients who desire quick recovery and minimal palpability. Conclusions: Hyaluronic acid skin filler products derived from an animal source are safe and effective. Successful clinical application should be based on an understanding of the patient's goals and the choice of a hyaluronic acid product with the optimal characteristics.