I guarantee that if I started smoking weed 30 times a day, my hair loss would not halt. A good friend of mine is an avid pot smoker - thinks marijuana is the fuckin' end all be all of humanity - and he's been steadily losing hair since he was about 20.
On the other hand, I'm the pinnacle of health: I rarely drink, I've never smoked a cigarette, cigar, or any substance of any kind; and I've taken maybe one "illegal" substance in my life. Further, my diet has been mostly broiled fish, white meat chicken, and vegetables since I was around 19 (and the first signs of hair loss began; my diet, however, was not a reaction to those signs).
I just don't see a correlation here, as there is to some degree with body hair -> male pattern baldness. I know that speculation will continue on this issue to no end, even if it's proven to be absolutely untrue - the very nature of the avid pot smoker is to promote the substance as the solution to all of humanity's problems.
