What is the ruling on using a hair mixture containing tobacco (smoke) from cigarettes, due to the belief that it has benefits for the hair?

Oils are permissible to use for hair. It is authentically reported that the Messenger of Allah (peace be upon him) oiled his head and enjoined honoring the hair and oiling it. Tobacco is pure, as the default for plants is purity. Many scholars have explicitly stated the purity of hashish. If the scientific benefit of tobacco in lengthening hair is proven, then there is no harm in using it. Not everything that is unlawful is impure, but everything impure is unlawful.