My hair started thinning last summer. I've lost about half of my hair density.
My hairline is still NW1, maybe NW1.5, it's just that my hair has become thin.
I used to have very thick hair. Interestingly it's thinning all over, not just in the typical MPB area. I think it's slightly thinner on top, but even the back and the sides are significantly thinner than two years ago.
I started taking vitamin D a few weeks ago. I also started using nizoral shampoo a few days ago because my head's been itchy for a while but there's no dandruff. If that doesn't help I'll consider fin or min, dermarolling etc.