A randomized controlled study to evaluate the depigmenting activity of L-ascorbic acid plus phytic acid - serum vs. placebo on solar lentigines

Background Solar lentigines (SL) are benign signs of sun damage that many people find distressing. Aim To assess the efficacy and safety of l-ascorbic acid 10% + phytic acid 2% for treating SL. Patients/Methods A double-blind, vehicle-controlled trial in 30 healthy subjects with 2 SL. Subjects were randomly assigned to apply product to one side of the body and vehicle to the other twice daily for 3 months with follow-up of 2 months. Results The pigmentation index for product-treated SL was reduced (maximum reduction 1.3 at 3 months [M3]), while that for vehicle-treated lesions remained stable. These differences were statistically significant for M1-M4 (P <= 0.003). Dermoscopy detected significant intergroup differences in pigmentation at M5 (P = 0.011). Colorimetry results indicated a statistically significant improvement in brightness (L*) between study drug and vehicle at M5. Fifteen subjects experienced 23 adverse events; six (mostly halo depigmentation) were judged possibly related to the study drug. There were six instances of mild-to-moderate intolerance in the study drug group and five in the vehicle-treated group. Conclusions Study treatment was significantly more efficacious than vehicle in many respects and was well tolerated. Future, larger studies are needed to confirm these results and to compare the product with gold standard treatments.