Rosemary oil is a popular ingredient in cosmetics due to its numerous beneficial properties. 

It is known to have antioxidant, anti-inflammatory and antimicrobial properties. It is also a natural astringent, which means it can help to tighten and tone the skin. This can help to reduce the appearance of fine lines and wrinkles, and improve the overall appearance of the skin. 

Additionally, Rosemary oil has been found to be effective in promoting hair growth and in treating hair loss. It can also be used to help with scalp conditions such as dandruff. 

Overall, rosemary oil is a valuable ingredient in many cosmetics and personal care products because of its beneficial properties for skin and hair.