I'm a 23 year old male. Over the course of the last year or so, my hair has become progressively thinner (not falling out, mind you - I have no signs of "proper" hair loss). I'd say the amount the number of hairs is the same (not counting the normal shedding, cycles, etc), but each strand is visibly thinner, for no reason I can pinpoint. The hair is straight and I keep it at about 2 inches length.
As for my general health, I'm quite thin (but still within the "normal" category in terms of body mass index) and experience difficulty gaining weight. I have allergic rhinitis, though can't see how that could be related. And I have been under a fair amount of stress, anxiety and depression in the last two or three years, with a few "ups" but mostly "downs", I'm afraid. I think (and hope...) there's nothing else.
Does anyone have any ideas?