Topical tretinoin for hair growth promotion

In a study from 1986, 56 subjects with androgenetic alopecia were treated with topical all-trans-retinoic acid (tretinoin) alone or in combination with 0.5% minoxidil for one year. The results showed that the combination treatment led to terminal hair regrowth in 66% of the subjects, while tretinoin alone induced hair regrowth in about 58% of the subjects. One female subject experienced significant hair regrowth using only tretinoin over 18 months. The study suggested that tretinoin may promote hair growth by stimulating cell proliferation and differentiation, as well as vascular proliferation, which are important factors for hair growth. These findings indicated the need for further research on the role of retinoids in hair growth and their potential synergistic effects with minoxidil.