Provillus - Version 2.0 Dihydrotestosterone (DHT for short) causes hair loss by shrinking the hair follicles resulting in atrophy of said follicles. Once the hair does fall out it cannot be replaced do to the atrophy. However the good news is that there are many DHT hair loss treatments available to reverse and possibly cure DHT so that you can keep your hair fuller and for a longer period of time.