Hi! I have heard this many times, even from quit educated people, that lack of calcium causes brittle nails. I know that nails contain protein - keratin, not calcium. And even if the body lacked calcium resorption from bones would first happen? So I dont see how it can cause brittle nails, but I have heard it so many times and so many people have claimed that it helps. So is this really a myth or there is some truth in it?