Table 1: Changes in MASI scores and colorimetric values for 4% HQ and 4% niacinamide-treated sides in 27 patients with melasma. Mast cell counts and melanin expression initially and after treatment with niacinamide in 11 patients.

HQNiacinamide
Onset8 wk Onset8 wk

MASI4 (.9–1.8)1.2 (.8–1.6)<0.0013.7 (2.9–4.4)1.4 (3.3–4.7)<0.001
L* axis50.9 (49.1–52.6)56 (54.6–57.4)<0.00151.1(49.3–52.9)56 (54.4–57.5)<0.001
a* axis12.9 (12.3–13.5)13.6 (12.6–14)0.2512.8 (12.1–13.5)13.6 (12.7–14.5)0.08
Mast cells/mm222 (15.1–28.9)16.3 (11–21.7)0.01
Stained Melanin (%)8.7 (8–9.5)6 (5.1–6.9)<0.001

MASI score was calculated for each treated half-face.
No statistical differences were found in redness (a*) for both treatments, before and after.
Final depigmentation Improvement (L*) did not show differences between both treatments ( ). In parenthesis, confidence Interval to 95%.