I often tie my hair in a half-updo, but I'm losing hair...

Whenever I dry my hair after a shower or look in the mirror at an angle, the thinning line running from the crown of my head to the side keeps catching my eye.

I used to think that hair loss usually starts from the center of the crown or the M-shaped hairline, but now that the hair on the sides of my crown is thinning and my scalp is starting to show, it doesn't cover well no matter which way I part my hair. I've tried using hair loss prevention shampoos and even giving myself scalp massages, but I can't seem to fix the loss of volume caused by weakened roots.

I can't tell if the thinning hair between the crown and the sides is simply due to scalp heat or stress, or if it is a typical early stage where I need to start hair loss medication.

For those of you who have visited a dermatologist or hair loss clinic because your hair has thinned mainly along the crown, what combination of treatments or management do you usually use?