When I was 22 I noted I had started thinning over the middle of my head. The hair density has gone way down were you can see through to the scalp in the right light, in various spots. I’ve not noticed it yet at the back of the top of my head nor the sides. The hair used to be naturally oily but now is more dry straw like.
I went to my GP and found I had low vitamin D and are taking supplements for nine days. But the NHS won’t give any further treatment unless you have bald patches and suggested a high protein diet and coconut oil, I think, massaged in.
This is a common problem in Nordic countries where there is not a lot of sun exposure to the general population year around.