Why aren't older men regrowing hair?

[himynameisj]

Since their testosterone level are really low when they age? Can someone explain it to me why their hair is not growing back?

 

[Vlatch]

Testosterone levels get lower but DHT levels get higher as we age.

 

[Ventures]

Testosterone levels get lower but DHT levels get higher as we age.

+ apparently AR sensitivity gets higher.