Study of DIOSHA S Lido Injection vs. YOUTHFILL Fine With Lidocaine in Treating Moderate to Severe Nasolabial Folds

Inclusion Criteria: * Adults aged 19 to 75 years * Voluntarily provided written informed consent * Moderate to severe symmetrical nasolabial folds (WSRS score 3 or 4 on both sides) * Agree to discontinue other facial dermatologic treatments (e.g., fillers, botulinum toxin, laser) during the study * Able to understand instructions and comply with study procedures Exclusion Criteria: * Active facial skin disease, infection, or untreated scars in the treatment area * History of severe allergy or hypersensitivity to device components * Facial aesthetic or invasive procedures in the treatment area within 6 months prior to screening * Use of prohibited medications within required washout periods * Participation in another interventional clinical trial within 4 weeks prior to screening or during the study * Pregnancy, breastfeeding, or non-compliance with contraception requirements * Any condition deemed inappropriate by the investigator