BackgroundMany new brands of hyaluronic acid (HA) fillers are being introduced, but comparative research on the characteristics of similar products is limited. ObjectiveTo test the efficacy, tolerability, and safety of a HA filler with lidocaine, Dermalax implant plus (Across), which is used for correcting nasolabial folds (NLFs), and to compare the performance of that of Restylane Sub-Q((R)) (Q-Med). MethodsA total of 52 subjects with visible NLFs were enrolled in this randomized, multicenter, patient/evaluator-blind, active-controlled, matched-pair clinical study. Each subject was injected with Dermalax implant plus in one NLF and Restylane Sub-Q((R)) in the other. All participants were reassessed for cosmetic changes at 2, 8, 12, 16, and 24weeks. Wrinkle severity was rated using the 5-point Wrinkle Severity Rating Scale (WSRS). ResultsAt week 24, the mean improvement in the WSRS compared to baseline was 1.060.54 for the PLUS side and 0.69 +/- 0.58 for the Sub-Q side (week 2: 1.67 +/- 0.58 and 1.21 +/- 0.67, week 8: 1.60 +/- 0.63 and 1.23 +/- 0.65, week 12: 1.58 +/- 0.61 and 1.15 +/- 0.61, week 16: 1.02 +/- 0.54 and 0.60 +/- 0.53). Average values of pain evaluated by self-assessment 100-mm VAS score within 30minutes after the procedure in the PLUS and Sub-Q groups were 14.65 +/- 16.23 and 38.29 +/- 27.27, respectively. Both fillers were well tolerated, and adverse reactions were mild. ConclusionWe confirmed that the monophasic HA containing pre-incorporated lidocaine (PLUS) is not inferior to well-studied biphasic HA (Sub-Q) in correcting to severe nasolabial folds for 24weeks and less painful than biphasic HA not containing lidocaine.