Try a Biotin gel supplement. Only one a day, don't miss a day though, and you'll find that within a couple of weeks your nails will become stronger , and your hair will break off less, especially if you have fine or damaged hair.
if you don't take it every day then the effect doesn't last, so ensure that you take one every day around the same time. It worked miracles on my hair and nails. I've got fine hair that breaks easily, and ditto nails, and I was at my wits end with it, even paying £30 every 3 weeks to have Gel nails to keep my nails looking good, but the ultimate problem with the Gel Nails is that when they're removed the natural nail can be severely damaged and even more paper thin than before, but since taking the Biotin capsule every day for the last year, I have no need for the Gel any more, and my hair is growing much faster because I'm not losing so much everytime I wash or comb it.