no / Cyclosporine A (CsA) has long been recognized as a potent hair growth stimulator in both humans and rodent. The induction of a dose-dependent hypertrichosis is one of the most frequent adverse effects of long-term CsA therapy (Lutz, 1994). However, it is unclear how this immunosuppressant induces hypertrichosis in patients or stimulates hair growth in human scalp skin transplanted on nude mice (Gilhar et al., 1988; Gilhar et al., 1991).