Until recently, I have been taking vitamin A supplements as one of my friends advised me to take it for hair growth, but it did not seem to help me, even after consistent intake for 3 months. My granny, however, has asked me to take vitamin B12 to prevent hair loss. I am in a fix, as I donât want to keep eating different vitamin supplements all day long for hair growth, therefore, I want to know from an expert out there, what is that you would consider best vitamin for hair growth? Please suggest.