>A good rule of thumb in biology and particular any kind of hormone production and balance is "use it or lose it" -

Very basic and very often wrong rule, so take it with a grain of salt.

Insulin for example is the opposite. "lose it then use it" would be a general rule for type 2 diabetics where insulin resistance commonly due to weight gain is the primary problem. Losing the weight leads to better uptake and usage. For a type 1 "lose it then use it" you typically lose the ability to produce insulin to an an autoimmune disorder, then are stuck using insulin for the rest of your life.

The body itself typically attempts to main homeostasis, but at population scales this is something that is going to have a massive range of ways it shows up. Evolution, at grand scales, doesn't care if you survive as long as enough of your population survives and breeds. At the end of the day you might just be one of those people that was born broken and to work properly you need replacement parts/chemicals. A working medical system should be there to figure out which case is which.