tincture is an ethanol extract from the fruit of Capsicum annuum Linneus, whose pungent component, capsaicin, stimulates hair roots to grow. Zinger tincture obtained from the ethanol extraction of the rhizome of Zingiber officinale Roscoe contains zingerone and shogaol, which promote hair growth by stimulating hair roots.
Glycyrrhizin and its derivatives as antiphlogistic agents, or hinokitiol, an antimicrobial constituent, are also used in hair care products. Glycyrrhizin is obtained from the root of Glycyrrhiza uralensis Fischer or Glycyrrhiza glabra Linne, both Leguminosae plants. Hinokitiol is an essential oil obtained by refining from Chamaecyparis
obtuse. It is generally well known that ginseng extract obtained from the roots of Panax ginseng (Araliaceae), a herbaceous perennial, is a cellular stimulant and that Polygoni multiflori radix, the tuberous root of Polygonum multiflorum Thunb (Figure 26), has inhibitory effects on sebum-filled hair follicles. At the present stage of research, the mechanism of hair growth and the cause of epilation having been elucidated, hair growth formulas are not always being developed. Among the previously mentioned various factors determining hair growth, one of the scientifically proven factors is androgenic hormone. Testosterone, a type of androgen, is converted to dihydrotestosterone (DHT), which has a powerful androgen action owing to 5_-reductase, the enzyme that converts testosterone into DHT inside the papillary cell of the hair follicle. It is assumed that DHT binds with
the androgen receptor inside the cell and it becomes the trigger of the incidence of male pattern alopecia.