Hi, I can’t answer all of your questions, but I can share my hair loss experience. I believe mine is due to the fact that I wasn’t absorbing nutrients. It’s also why I lost so much weight in spite of consuming 2500 calories a day (I am 5’5″ 104 pounds. I am usually 115). I believe it’s due to digestive issues, intestinal damage or perhaps leaky gut. In any case, I started taking Biotin and was told it takes a few months to notice a difference. I think once my digestion is healed, my hair loss will stop. It has slowed down a bit. Fingers crossed.