It depends on what is happening at the follicle. Shedding from a temporary trigger — stress, illness, childbirth — usually recovers on its own once the trigger passes. In pattern hair loss, follicles miniaturize gradually; treatment can often thicken miniaturized hairs and protect what remains, but follicles that are long gone do not come back, which is why timing matters so much.
Transcript
It depends entirely on one thing. A follicle that has shrunk is still alive and can still make hair. A follicle that has closed and scarred cannot. From the outside, they look identical, which is exactly why guessing is useless. Under magnification, a doctor can tell them apart in minutes. That's the difference between waiting and knowing.
Where the line sits on your scalp is a clinical question. A doctor can tell you which zones are recoverable and which are not — and standardized imaging then tracks what actually happens rather than what anyone hoped. Individual results vary.