If that seems like a long time, consider this: That’s three times faster than toenails. Interestingly, the nails on your dominant hand grow more speedily than the ones on your non-dominant hand. (Which is a good thing if you find yourself breaking more nails on your stronger side!) Want to help your nails grow strong and healthy? Try a biotin supplement—or munch on some leafy swiss chard, which is packed with the stuff.