This is the study that measured testosterone, epitestosterone, and DHT in the hair follicles of balding guys.
https://www.jidonline.org/article/S0022-202X(15)41116-9/fulltext
Here's the result:
What stands out most to me is plain old testosterone. Bald men have a lot more testosterone in their hair follicles. But as you know, they don't have any more testosterone in their blood than non-balders, and don't display the good "results" of testosterone in the body any more than non-balders. Anecdotally, I think they display a lot less! And at least in premature balders ("Male PCOS"), the studies confirm this.
It makes me think of calcium and vitamin K2. Calcium is good in the bones and bad when it inappropriately gets into soft tissue. Vitamin K2 somehow keeps calcium in the bone and out of soft tissue.
Some unknown factor puts testosterone where it should be and keeps it out of where it shouldn't be - the hair follicle. (and perhaps other places?)
When that unknown factor is not functioning well, testosterone is less present where it should be and more present where it shouldn't be.
Another question is what function do hormones have in hair follicles? What would testosterone be doing in your hair? What good does it think it's doing up there haha? Seems to me that it shouldn't be there at all. So WHY does it show up there?
Also I'd like to know how and why DHT has the function of miniaturizing hair in the first place. How does it do that? (I don't agree with the alternative claim that DHT doesn't cause hair loss. It absolutely does. DHT directly miniaturizes hair follicles right away in lab tests. However I do agree with the claim that DHT is good for you and that "high DHT men" often have plenty of hair. Because it's the varying levels in the different tissues that matter.) So how and why does DHT miniaturize hair? What purpose is it fulfilling, or attempting to fulfill but going off course instead?