The Promoting Effect of Rosemary Oil on Hair Growth by Gross and Histological Observation in C57BL/6 Mice

The study investigated the effect of rosemary essential oil on hair growth in C57BL/6 mice, dividing male mice into four groups: normal, vehicle control, positive control, and experimental. After 4 weeks of daily topical applications, hair regrowth was significantly faster in the rosemary oil (42%) and minoxidil (55%) groups compared to the normal (3%) and vehicle control (20%) groups. Histological observations showed that the rosemary oil and minoxidil groups had higher hair follicle numbers, follicle depth, and dermal thickness, along with fewer mast cells. These findings indicated that rosemary oil effectively stimulated hair growth in this animal model.