Topical Niacinamide 4% and Desonide 0.05% for Treatment of Axillary Hyperpigmentation: A Randomized, Double-Blind, Placebo-Controlled Study

This study evaluated the efficacy of topical niacinamide 4% and desonide 0.05% in treating axillary hyperpigmentation in 24 women aged 19–27 years with skin phototypes III–V. Over 9 weeks, both treatments showed significant colorimetric improvement compared to placebo, with desonide demonstrating a superior depigmenting effect. A good to excellent response was observed in 24% of cases for niacinamide, 30% for desonide, and 6% for placebo. The study found that decreased pigmentation in desonide-treated axillae was linked to the recovery of basal membrane disruption, suggesting that the depigmenting properties of niacinamide and desonide may be due to their antimelanogenic and anti-inflammatory effects, respectively.