Will Repeated Intense Pulsed Light (IPL) Combined With Lactobionic Acid Affect Facial Skin Sensitivity in Photoaged Skin? Results of a Six‐Month, Prospective, Randomized Split‐Face Study

Background Lactobionic acid (LBA), a novel polyhydroxy acid structurally related to alpha‐hydroxy acids (AHAs), has emerged as a multifunctional ingredient in cosmetic dermatology owing to its excellent biocompatibility, moisturizing, and antioxidant properties. Intense pulsed light (IPL) represents a well‐established, broad‐spectrum light‐based modality for various aesthetic dermatologic indications. Nevertheless, the potential impact of concurrent LBA application on facial skin sensitivity during IPL treatment has not been fully elucidated. Methods Twenty‐two photoaged volunteers were enrolled in the study. Each participant received five sessions of IPL treatment at 1‐month interval on both sides of the face. One side of the face was randomly assigned to receive an adjunctive application of a 6% LBA formulation in combination with IPL, while the contralateral side served as the control (IPL alone). Objective biophysical parameters such as transepidermal water loss, stratum corneum hydration, thickness of the skin, and erythema index were collected at baseline (BL) and at 1 month after the first IPL treatment, 1 month (M1), and 3 and 6 months after all 5 IPL treatments had been given. The lactic acid sting test (LAST) and Sensitive Scale 10‐item version (SS‐10) were performed at BL and M1. Results Twenty volunteers completed all treatment sessions and the 6‐month follow‐up period. No statistically significant difference was noted between the combined treatment and IPL‐alone side in terms of the objective biophysical parameters, LAST, or SS10 evaluation ( p > 0.05). No irreversible adverse events were noted during the treatment sessions and at the follow‐up period. Conclusion Combining IPL treatments with 6% LBA product does not compromise facial skin barrier function or increase skin sensitivity. Trial Registration: Chinese Registry of Clinical Trials: ChiCTR2400083642