ETD is a topical solution containing the active ingredient: Alfatradiol, also known as 17α-estradiol or as 17-epiestradiol.
Alfatradiol is a steroidal weak estrogen and potent 5α-reductase inhibitor used topically in the treatment of androgenic alopecia (pattern hair loss). The drug inhibits the conversion of testosterone to the metabolite dihydrotestosterone (DHT) by suppressing 5α-reductase activity.
It also accelerates the conversion of testosterone to estradiol by stimulating aromatase, decreasing the level of testosterone and leading to a reduction in DHT. In addition, the drug has been reported to stimulate the generation of hair follicular matrix cells.