Thank you! I will be reading at all of these links. In the meantime, if you have a quick recommendation for a brand of biotin that is particularly efficacious and healthy, please let me know. I just went to Vitamin Shoppe and looked at the many alternatives there and it was pretty overwhelming to try to compare. I know I need to do more reading! I was using one but now that I look at the others I suspect the one I was using was not really a pure enough product, as it has too many additives.