Preparations of the Cymbopogon citratus leaves are used in folk medicine for the treatment of inflammatory processes. The present study investigated the proposed anti-inflammatory properties of C. citratus essential oil (EOCC) in human skin in vivo using the methylnicotinate (MN) microinflammation skin model. Skin exposure to MN causes a disturbance that triggers the production of reactive oxygen species and evokes a short duration microinflammatory reaction that might be explored to meet this objective. Fourteen participants of both sexes were selected after providing informed consent. Three areas (3 cm × 3 cm) were drawn on both forearms. One randomly chosen area was treated for 14 days, twice a day, with a polyacrylic acid gel containing 5% EOCC. Remaining areas were used as controls. Results revealed a clear protective effect at the EOCC-treated site. The MN reaction showed significantly lower transepidermal water loss, blood perfusion, erythema, and edema when compared with the other areas. Furthermore, the methodology here proposed is an innovative approach to study the clinical impact of these substances on human skin, contributing to an evidence-based support regarding the interest of using these products in human health.