There's a common misconception that prenatal vitamins have positive effects upon non-pregnant women. For instance, you might have heard that they will help increase your rate of hair growth or strengthen your hair. This may not be true since prenatal vitamins will most likely not have more of an effect than a typical multivitamin. Understanding the role of prenatal vitamins and their content may help you talk with your doctor about the pros and cons of using them for hair growth or other reasons other than pregnancy.
Your hair is part of your integumentary system, which includes the skin and nails as well. Even though product manufacturers claim that your hair needs nourishment, the reality is that hair itself is neither cellular nor living -- it's merely protein-based material produced by living cells within the skin in the hair follicle. As such, hair doesn't need vitamins or minerals, though follicle cells -- like all living cells -- do. In general, however, extra vitamins won't make follicle cells produce hair faster or make hair stronger.
Prenatal vitamins aren't significantly different from regular daily multivitamins. They contain many of the same vitamins and minerals that you'd find in a women's daily supplement pill, though the amounts of nutrients are adjusted to meet the needs of pregnant women. In particular, prenatals contain large quantities of iron and folic acid. Drs. Michael Roizen and Mehmet Oz, in their book "You: Having A Baby," explain that pregnant women need the extra iron and folic acid in prenatal vitamins to provide for specialized pregnancy needs.
In general, taking vitamins -- prenatal or otherwise -- to benefit your hair isn't going to have any particular effect, unless you're truly vitamin deficient. If you are, you'll benefit by taking a regular daily multivitamin and by ensuring that your diet contains plenty of vitamin- and mineral-rich foods, especially fresh fruits and vegetables. Neither of the nutrients that truly distinguish prenatal vitamins from regular multivitamins -- iron and folic acid -- affect hair significantly.
The reason it's so common to hear that prenatals help make your hair grow faster and stronger is that many of the women on prenatal vitamins have luxurious, fast-growing hair. This is not due to the vitamins, however. Instead, it's a result of pregnancy hormones, which cause increased blood flow to the skin, explain Heidi Murkoff and Sharon Mazel in their book "What To Expect When You're Expecting." You can't duplicate this effect with prenatals.