HA rarely induces immunogenic reactions and is stable enough to be used in combination treatment regimens, as it has no species or tissue specificity. Moreover, another advantage of HA is that it is easily degraded by hyaluronidase. The HA filler used in this study, Glytone 3, consists of 23 mg/ml HA in phosphate buffer with mannitol, which acts as both an antioxidant and a moisturizer.