I have been losing a fair amount of hair, (considering I'm a 20 year old girl with no signs of thyroid problems or hair loss in my family) and I was told by quite a few people it had to do with vitamin, (specifically iron & b12) deficiency. for the last 3 days or so I have been taking iron pills and a multi vitamin but my hair is still falling out and I wanted to know how long vitamins took to have an affect on that sort of thing.. Thanks..