What Does DHT Do to Hairs?

How exactly does Propecia work? I have searched online for an answer but have only come across the phrase, “Propecia blocks DHT, which is a hormone… that leads to hairloss.” I was wondering if there is a more specific explanation to what happens.

Does DHT somehow tighten the skin around hair follicles, which would imply that Propecia relaxes the skin around hair follicles so as to relieve stress around the follicle? Or does DHT reduce the strength of the hair itself? Does it kill cells at the bottom of follicles, which would imply that Propecia prevents DHT from reaching these cells?

Genetic balding causes hair follicles to undergo a process called apoptosis (cell death). Hairs grow in cycles that last about 3 years for the average person. In the genetic balding process, somewhere between 7-10 hair cycles, hair death is triggered by the hormone DHT. When you take a DHT blocker (Propecia/finasteride), it prolongs the number and length of the hair cycles to allow it to keep growing.

See Why Does Propecia Eventually Lose the Battle to Genetics? for more info.