The reason more hair is lost with aging is because its been exposed to DHT with a long long time, and the hair shaft has diminished in size.
This happens much slower in women, and even there its hereditary, but it happens all over the head.
Eventually DHT kills the hair folicle, fast or slow, choose your poison.
Spiro does help hair loss, with less T, there's less DHT, so there's less less DHT getting to T receptors at the hair folicle.
Also, Spiro blocks the T receptors directly, but since it has a short half life and doesn't block all receptors, some DHT from T coming off the adrenals gets to the hair shaft.
For many people, the hair is not that sensible and the small amount will not affect hair significantly, but for others very sensible to DHT, hair loss will continue, but at a much lower speed.
For everyone though, cutting most DHT entirely will enable the hair that's folicle that's not dead yet to very slowly recover in the space of years.
There is a more DHT in older men, less in fact as testosterone goes down with age, that's why hair loss often slows down when men hit their 50's.
In women, its a bit more complicated, estrogen increases the length of time the hair is in its active phase. There are more active hair at a time and hair is denser.
At menopause, estrogen goes down, the hair cycle is shorter, and there's less estrogen inhibiting T action from the adrenals and so, DHT starts to have more impact on the hair shafts. So, you get a reduced density and the hair that's there is attacked by DHT more.
The hair is most vulnerable to DHT when its dormant, with less estrogen, the hair is dormant longer and from cycle to cycle, in people sensible to it, the hair shaft becomes smaller.