MPB or General Age-Related Thinning?

How can you tell the difference between male pattern baldness and general thinning as you age? I am almost 35 and have no discernible signs of MPB other than a mature hairline (which appeared when I was about 19). However, I am convinced my hair is thinner than it used to be.

Simple answer: There is a pattern to MPB. That is why they call it male “pattern” baldness and this is the classic male genetic hair loss.

There are other diseases that cause general thinning, including diffuse unpatterned alopecia (DUPA), senile alopecia, etc. You can have that diagnosis made for sure by comparing the bulk in different parts of your scalp. A knowledgeable doctor will add value in examining you.