Pregnant women experience longer, fuller hair during pregnancy. It’s a well-known perk of the process. Most women today also start taking prenatal vitamins during pregnancy in order to get all of the vitamins and minerals needed to grow a healthy baby and prevent developmental problems. Prenatal vitamins contain many of the nutrients that people associate with healthy hair growth, such as Biotin, Vitamin B, calcium and iron, so they must be the reason pregnant women have thicker, faster-growing hair – right?


Prenatal vitamins have a popular reputation for helping women grow stronger and longer hair and nails, but this is a case of correlation does not imply causation. There’s a scientific reason for the change in pregnant women’s hair, but it’s not the prenatal vitamins.

Why does hair grow during pregnancy?

Every strand of hair goes through three different growth stages:

Right now you have hairs and hair follicles in all of these various growth stages on your head. During pregnancy the elevated hormone levels prevent the hair from reaching the final phase of fall out, as obstetrician-gynecologist Kameelah Phillips, M.D., explains: “During pregnancy the cycle of hair loss is arrested resulting in fewer lost strands while their hair continues to grow. This is largely a hormonal effect and not related to the prenatal vitamin.”

What do prenatal vitamins do?

Pregnant women, and women who are planning to conceive, require increased amounts of certain vitamins and minerals, such as folic acid, iron, and calcium to help their babies develop, and to prevent defects and pre-term delivery. They also provide the mother with the nutrients she needs to support this growth. For example, Wendie A. Howland, MN RN-BC CRRN CCM CNLCP LNCC, a certified nurse in life care planning, told NaturallyCurly, “When you grow extra blood volume to support pregnancy, you need extra iron to make the hemoglobin molecules in red blood cells.” That is why the recommended daily intake of iron for pregnant women is 27 milligrams, while women who aren’t pregnant only need 8-18 mg a day, depending on your age. Similarly, pregnant women have a recommended daily intake of 600 micrograms of folate or folic acid, while women who aren’t pregnant only need 400 mcg a day. According to Dr. Phillips, “Too much of a vitamin or nutrient can be a bad thing, depending on your health, and whether the body can easily get rid of excess.” Many vitamins are water-soluble, and your body can get rid of what it doesn’t need, but Andrew Weil, M.D. points out that “...iron is one of the few minerals we cannot eliminate (except through blood loss), and accumulations in the body can quickly rise to toxic levels. Iron is an oxidizing agent that can increase the risk of cancer and heart disease.” Because of this, he recommends that you “...never take iron supplements unless advised to do so by a physician after tests have revealed iron deficiency anemia.”

Can you take prenatals if you’re not pregnant?

It is best to always consult your doctor first, but Dr. Phillips says “as long as a woman stays within the allotted daily requirements for nutrients then there is minimal risk.” She does warn against taking them along with other supplements as there may be overlapping ingredients. Technically, as long as you are not taking an excess of your daily recommended intake of vitamins and minerals, you can take prenatals – but what will they do for you?

Will prenatal vitamins make your hair grow?

There is no scientific evidence that suggests prenatal vitamins can make your hair grow. Dr. Phillips says, “Women should not expect magical growth from a prenatal vitamin.  This comes with proper hair care and patience.  I don't recommend spending a lot of money on these supplements expecting a miracle - you may be disappointed.” Nurse Wendie A. Howland adds, “If somebody is clinically malnourished, s/he will lose hair, and vitamins might help, but it takes a lot to be clinically malnourished enough for them to work. If people think taking prenatal vitamins will be responsible for waking up those slumbering follicles, they’re going to be disappointed.”

If you aren’t pregnant, or aren’t planning to be pregnant, and are considering taking a prenatal vitamin for cosmetic reasons, don’t. There are plenty of other ways that you can contribute to your hair health, like eating a healthy, balanced diet and having a consistent hair care regimen. Dr. Phillips says, “People should be aware that supplements or vitamins should not be used as a substitute for a healthy, balanced diet. Also, there is no vitamin or supplement that will repair the effects of chronic poor hair practices, i.e. tension, excessive heat, chemicals etc. It is important to remember the basics of healthy hair care.">

Always consult a medical practitioner before incorporating a supplement into your diet!

What's next?

Grow healthy hair from the inside out with this Hair Growth Diet.

NaturallyCurly Editor Devri Velazquez took two different beauty supplements, read her review in "Why I'm So Over the Beauty Vitamin Hype."

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This article was originally published in 2016 and has been updated.