A Randomized, Double-Blind, Multicenter Comparison of the Efficacy and Tolerability of Restylane Versus Zyplast for the Correction of Nasolabial Folds

Bovine collagen is extensively used for facial soft tissue augmentation but provides only temporary correction and can cause hypersensitivity reactions. Hyaluronic acid derivatives potentially offer improved longevity of correction and a reduced risk of immunogenicity and hypersensitivity.To compare the efficacy and safety of nonanimal stabilized hyaluronic acid gel (Restylane; Q-Med, Uppsala, Sweden) with that of bovine collagen (Zyplast) for treatment of nasolabial folds.One hundred thirty-eight patients with prominent nasolabial folds were randomized to treatment with hyaluronic acid gel and bovine collagen on contralateral sides of the face. Treatments were repeated at 2-week intervals, as required, to achieve "optimal cosmetic result" (baseline). Outcomes were evaluated by a blinded investigator at 2, 4, and 6 months after baseline.Less injection volume was required for "optimal cosmetic result" with hyaluronic acid gel than with bovine collagen, and patients and investigators judged hyaluronic acid gel to be more effective in maintaining cosmetic correction. The investigator-based Wrinkle Severity Rating Scale and Global Aesthetic Improvement Scale assessments at 6 months after baseline indicated that hyaluronic acid gel was superior in 56.9% and 62.0% of patients, respectively, whereas bovine collagen was superior in 9.5% and 8.0% of patients, respectively. The frequency, intensity, and duration of local injection-site reactions were similar for the two products.Nonanimal stabilized hyaluronic acid provides a more durable aesthetic improvement than bovine collagen and is well tolerated.