I had been taking one 1500mcg of Rexall brand biotin for awhile and never noticed any itching til I started taking 2 of em and Follicure HSN pills. My head itched so bad I had everyone in my house to look @ my scalp as I parted it and they all said there was no dandruff @ all so I still greased my scalp w/ sulfur 8 and it helped a little but after awhile maybe 1 week it stop but hair had grown alot by time I did a retouch.I was also stretching.