Question

what causes nails and hair to grow? also what is the normal rate of growth for hair and nails?

Answer 1

A deficiency of the B vitamins can cause nails to not only lack in growth, but they can also become fragile and break easily. Lack of B12 specifically can cause nails to be dark-colored and dry. B vitamins are also essential to hair health, to prevent breakage and encourage new growth. B12 can be taken as a vitamin by itself or can be found in clams, liver, fish, eggs and cheese, among other foods.

Answer 2

Keratin is a special type of cell in your skin that makes up your hair and nails. As keratin cells naturally push upward through the skin, they die and then harden, turning into your hair or nails. Known as keratinization, this process is what makes hair and nails grow, and several factors contribute to its sustained momentum. Hair grows an average of 3 inches a year, whereas nails usually grow about 1 1/2 inches a year.

Read more: http://www.livestrong.com/article/181963-what-makes-your-hair-nails-grow/#ixzz210GvN1MQ