Nails and hair are both made of keratin, so it isn’t surprising that a lot of the same nutrients help to strengthen both. Vitamin A and D and calcium help prevent nail brittleness, while Vitamin B 12 helps retard dryness. Deficiency of another B vitamin, folic acid, has been linked to hangnail formation, as have a lack of vitamin C and protein. Hangnails can inflame the tissue surrounding the nail, as can a lack of essential fatty acids. Among the minerals , magnesium helps keep the nails from becoming soft and brittle and a lack of iron can result in thin. pale nails. Organic sulfur is essential for healthy skin, hair and nails, which you can find in MSM.