Efficacy and safety of a new monophasic hyaluronic acid filler in the correction of nasolabial folds: a randomized, evaluator-blinded, split-face study.

Hyaluronic acid (HA) fillers are frequently used for the correction of facial soft-tissue defects. To compare the efficacy and safety of a novel monophasic HA filler (mono-HA), and a well-studied biphasic HA filler (bi-HA), in the treatment of moderate to severe nasolabial folds. In this randomized, evaluator-blinded, split-face comparative study, subjects were randomized for injections with mono-HA or bi-HA on the left or right side of the face. Efficacy was determined by calculating the change in the Wrinkle Severity Rating Score (WSRS) relative to baseline. Local safety was assessed on the basis of subject diary entries which recorded erythema, swelling, induration, pruritus, irritation, mass, hematoma, pain, and dryness. At week 24, the mean improvement in the WSRS from baseline was 2.18 ± 0.42 for the mono-HA side and 2.16 ± 0.41 for the bi-HA side. Both fillers were well-tolerated and adverse reactions were mild and transient in most cases. Mono-HA has a non-inferior efficacy to bi-HA in the treatment of moderate to severe nasolabial folds.