Mangosteen Gel Applied Before NB-UVB Exposure in Healthy Adults

This study examined whether a gel containing mangosteen (\*Garcinia mangostana\*) pericarp extract could reduce short-term skin redness caused by narrowband ultraviolet B (NB-UVB) exposure when applied before irradiation. Healthy adults aged 20-45 years with Fitzpatrick skin phototype III or IV participated. Six small test sites were marked on each participant's back. Each site was assigned to one of six conditions: mangosteen gel containing 5%, 10%, or 20% extract; gel base without extract; NB-UVB exposure without topical treatment; or no topical treatment and no NB-UVB exposure. Because all six conditions were evaluated in the same participant, each participant served as their own control. The active gels and gel base were applied 20 minutes before NB-UVB exposure. The ultraviolet dose was based on each participant's individual skin sensitivity. Skin redness and lightness were measured with a color-measuring instrument before exposure and at 12, 24, and 48 hours afterward. The investigator performing the skin-color measurements was not informed which condition had been assigned to each test site.