Efficacy and safety of a topical cream containing terpinen-4-ol and niacinamide following 1064-nm picosecond Nd:YAG laser treatment for facial hyperpigmentation reduction

Background This study evaluated the efficacy and safety of a topical cream containing terpinen-4-ol and niacinamide after 1064-nm picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) laser treatment for reducing facial hyperpigmentation.Methods This split-face study was conducted between December 2025 and March 2026 and included 27 patients who underwent treatment with a 1064-nm picosecond Nd:YAG laser. The right hemiface received a topical cream containing terpinen-4-ol and niacinamide immediately after laser treatment, whereas the left hemiface received laser treatment alone. Skin pigmentation was assessed using an automated skin analysis device. Melanin severity scores (MSSs) were evaluated on both hemifaces at baseline and 4 weeks after treatment. The right and left hemifaces were compared at baseline and 4 weeks after treatment.Results Skin pigmentation scores improved significantly on both hemifaces from baseline to 4 weeks after treatment (P<0.001). However, the improvement was greater on the right hemiface than on the left hemiface, and this interhemifacial difference was statistically significant (P=0.004). Similarly, MSSs improved significantly on both hemifaces from baseline to 4 weeks after treatment (P<0.001). The improvement in MSSs was significantly greater on the right hemiface than on the left hemiface (P<0.001).Conclusions Applying a topical cream containing terpinen-4-ol and niacinamide after 1064-nm picosecond Nd:YAG laser treatment was associated with greater reduction in skin pigmentation than laser treatment alone and appeared to be a safe adjunctive therapy, with no reported complications.