What are some good treatments for diffuse thinning (hair loss/thinning not affecting hairline) and when it's too late to take action?

[TooYoungToBeBald]

It's ridiculous. My hairline is not receding at all, but the top portion of my scalp is just a little more than light fluff. I'm not sure if it wouldn't be better to just shave it all off...
Is there still anything I can do with it? And if so, when will be my last chance to start acting? When there's absolutely nothing left? Or is it already too late?

 

[NW9000]

propecia and rogaine

 

[jazz1]

Post pictures….