I have been having hair thinning problem since last 6 years. My hair shed in less number & doesn't grow back. Due to which my scalp is visible. I consulted a dermatologist where she asked me to take few test like thyroid, iron study, vitamin b12, vitamin D & Serum ferretin. My serum ferretin is 8 which is very less so doctor asked me to take iron injection. Kindly confirm me on this. Whether it is going to cause any side effects, & how far it is effective.