I take Dollar General brand Hair, Skin, and Nails vitamins. I looked into Nourishair and the other GNC one, but they don't contain any calcium. I like the DG one because it is essentialy a multivitamin with biotin, silica, and some other things added to it. It doesn't have any iron, but like you said, tini, too much iron can be bad. I can't take One-A-Day vitamins because of the iron content. I would eat with them and still get nauseous. I read that as long as you have meat in your diet, you should get enough iron. Many cereals are fortified with iron, too.
I've only been taking the DG vitamins for about a month, so I haven't seen any change yet. My nails though are stronger and grow quickly. Guess that is a good sign. Do you take the GNC formulas twice a day, or 3 times? I'd thought about trying Nature's Bounty hair vitamins, but you have to take them 3 times a day. 2 is enough for me - I have a hard enough time remembering to do that. I'm going to try these vitamins for a month or two more, and see what happens.