Biotin. It’s what many women take for thick, healthy hair and radiant skin . But there’s a more important function of biotin that’s fundamental to life itself (with more scientific evidence, to boot) – and that’s why you find biotin in most high-quality prenatal vitamins.
What is biotin?
A water-soluble B vitamin, biotin helps facilitate a number of metabolic processes that break down the three macronutrients: Carbohydrates, fats and protein. In these metabolic reactions, biotin serves as a coenzyme for five carboxylases that help metabolize glucose (from carbohydrates), fatty acids (from fats) and amino acids (from protein). Because biotin is necessary for the body to convert these nutrients from foods into energy, biotin is essential in our normal growth and overall health.
Biotin is essential for life itself – in fact, "biotin" comes from the Greek word bios, which means to live. From bacteria to plants to animals, a wide range of living organisms need biotin for metabolism, gene regulation and cell signaling. Plants and bacteria, including the gut microbiota in humans, synthesize biotin.
Does biotin improve your hair, skin and nail?
Most people associate biotin with luxurious hair, supple skin and smooth nails. Cosmetics and supplement companies have marketed biotin this way, based on the fact that severe biotin deficiency affects hair, skin and nails. However, there isn’t enough scientific evidence yet to support the claim that additional biotin for people who already have adequate levels of biotin can improve hair, skin and nails.
If not for healthy hair, skin and nails, why would you take biotin? And why is it in prenatal vitamins? That’s because biotin’s role in our basic metabolic functions is essential for the baby’s healthy growth in utero.
Biotin supports baby’s healthy growth in utero
Many prenatal vitamins include biotin to support the normal development of the baby. While human, in vivo evidence is still building, animal and in vitro studies have suggested biotin’s potential importance in the early stages of embryo development:
- One animal study found that a particularly large amount of biotin was absorbed into ovarian follicles just before ovulation, possibly in preparation for its need after fertilization.
- A number of animal studies have found an association between low biotin levels and fetal malformations.
- An in vitro study of human cells also suggested that a sufficient level of biotin may be potentially necessary for normal palate formation.
- On the male side, one in vitro study of frozen sperm found that addition of biotin to the culture medium may potentially support sperm’s motility (ability to move), fertilization rate and early embryonic development.
So, it’s important to start taking prenatal vitamins when you are planning to get pregnant or actively trying – i.e., before you know you are pregnant. Like folic acid (or folate, which helps baby's brain develop normally), biotin may be important for very early embryonic development, and you may not know that you are pregnant when your developing baby needs biotin.
Pregnant and nursing women may be low in biotin
There is another reason selecting a prenatal multivitamin with biotin – and staying on it until you are done nursing – is a good idea: Studies have shown that about a third of pregnant women can develop low-level biotin deficiency. Surprisingly, this even applies to women with a level of biotin intake currently considered sufficient. While scientists don’t know why it happens, biotin levels in the blood and urine also decline when nursing.
Because of this yet-unexplained drop in biotin levels, pregnant and nursing women are considered an at-risk group for biotin deficiency. (Biotin deficiency is otherwise quite rare among healthy people who eat a varied diet.)
How much biotin do you need?
The US National Academies of Sciences recommend 30 mcg/day of biotin for adult women and pregnant women, and 35 mcg/day for nursing women. However, as we saw above, these official recommendations may not be enough for up to a third of pregnant and nursing women. We recommend speaking with your OBGYN provider to understand your real biotin needs.
Don’t take too much biotin
That said, don’t take more biotin than you need, or recommended by your healthcare provider. Biotin can interfere with some blood test results, including hCG (the hormone measured in pregnancy tests), TSH and other reproductive hormones. Depending on the test, a high level of biotin in your blood can skew the test results higher or lower than reality. (According to the FDA, some lab test providers have updated their assays to account for the problem, but there are some that still need to be addressed.)
Getting an incorrect blood test results can be life-threatening in extreme cases; even in less extreme situations, it could mean you don’t get the treatment you need, or receive one you didn’t need. Your doctor should ask you if you are taking supplements containing biotin, but even if they don’t, let them know. Some doctors may recommend temporarily getting off biotin-containing supplements for a few days before your lab tests, too.
