I'll give you the ones I know.
My dermatologist says most times it is caused by the pore getting smaller or clogged by excess scalp oil. It gets dry, harder to take off with mere shampoo, then the pore cant breath, and hair starts thinning.
He recommended my brother to go bold first so he could treat deep his scalp and specially sent him scalp massages to stimulate the blood flow. It was more a patience skill... he had to wash his scalp twice a day and massage for 1 hour every f...ng day.
It did work.
