Comparison of Clinical Outcomes between Hyaluronic and Polylactic Acid Filler Injections for Penile Augmentation in Men Reporting a Small Penis: A Multicenter, Patient-Blinded/Evaluator-Blinded, Non-Inferiority, Randomized Comparative Trial with 18 Months of Follow-up.

Although several types of penile augmentation (PA) fillers have been recently introduced, no long-term follow-up studies have compared them. This study aimed to compare the long-term clinical outcomes of hyaluronic acid (HA) and polylactic acid (PLA) filler injections for PA. Our multicenter, patient-blinded/evaluator-blinded, randomized comparative trial was performed for 18 months after the single injection of fillers. Sixty-seven healthy men reporting a small penis were administered an injection between November 2016 and May 2017. Subjects were divided into the HA group (n = 33) and PLA group (n = 34). At 18 months, the mean penile girths had significantly increased in both groups (each p < 0.001). Changes in the mean penile girth of both groups were not significantly different during the study period. Satisfaction levels at 18 months were significantly higher than those at baseline in both groups (each p < 0.01). Changes in satisfaction levels did not differ significantly during the study period. Injection-associated adverse events (AEs) occurred in three (9.1%) patients in the HA group and in two (5.9%) patients in the PLA group; no serious AEs occurred. In conclusion, HA and PLA filler injections for PA led to significant augmentation and increased satisfaction. Clinical efficacy and safety were comparable between groups.