DHT stands for Dihydrotestosterone. It’s a by-product of the male hormone called testosterone. Hair loss in vast majority of men is caused by DHT alone.
Testosterone converts to DHT with the aid of an enzyme called 5-alpha-reductase. The DHT is then induced into the blood and flows to all the parts of the body including your head scalp. The process of testosterone converting to DHT is not abnormal and happens in every man. However, it creates problems in those men who are genetically sensitive to DHT. In such men, DHT causes hair loss and eventually makes all the hair, whose hair follicles are affected by DHT, disappear.
DHT over a period of time, shrinks the hair follicles to an extent that the follicle is no longer capable of producing new hair or contribute towards hair growth cycle.
There are many drugs available that can directly impact the testosterone-to-DHT conversion process and reduce the amount of DHT produced and induced into the blood. This can dramatically slow down the hair loss and also stop it completely.
Such drugs must be taken for a very long period of time and if you stop taking the drugs, all the hair that are receiving the benefit of the drug will eventually fall out after some time.