PRP targets androgenetic alopecia, the hereditary hair thinning that affects both men and women. Experts believe it may also be effective for women with traction alopecia, hair thinning caused by too-tight ponytails, braids, other styles and salon procedures like straightening, colouring that pull the hair out. According to researchers, the best candidates are people who have only recently begun to lose hair. PRP won’t work for anyone who’s completely bald and it won’t completely regrow all lost hair.