The Scoop - Spring 2018

What’s the Scoop on Dietary Supplements for Hair, Skin, and Nails?

Dietary supplement products that are promoted for healthy hair, skin, and nails are readily available, but do they work? Formulations differ, but almost all contain very high doses of biotin.

Biotin is a B vitamin found mainly in meat, eggs, fish, nuts, and some vegetables. A biotin deficiency can cause skin rashes, hair loss, and brittle nails––hence, the belief that taking extra biotin will produce glowing skin, thick hair, and strong nails. But do these claims actually hold up?

Biotin is naturally present in some foods, such as salmon and eggs.

One of the most common misconceptions about vitamins and minerals is that if a nutrient deficiency causes a particular set of symptoms, then taking more of that nutrient will not only reverse those symptoms, but will actually leave you better off. The reality is, if you are already getting enough, getting more doesn’t usually help.

Biotin helps metabolize the food we eat into the energy we need. The recommended amount of biotin for adults is 30 micrograms (mcg) per day, and you can get this much by eating a wide variety of nutritious foods. For example, a meal with 3 ounces of salmon, 3/4 cup of cooked sweet potato, 1/2 cup of cooked spinach, 1/4 cup of roasted almonds, and 1 cup of 2 percent milk provides about 11 mcg of biotin.

Some dietary supplements contain between 2,500 and 5,000 mcg of biotin, which are very high doses. In a few small scientific studies, some people with thin and brittle nails who took high doses of biotin had harder nails. And in a few cases, high doses of biotin improved a rare hair disorder in children and skin rash in infants. But the results of these studies are too preliminary to recommend biotin for any of these conditions.

Biotin doesn’t have an upper intake limit because there’s no evidence that it’s toxic, even at high doses. Most vitamins and minerals, however, do have upper limits, and getting too much can be unsafe. Some can also interact with medications or lab tests. Biotin, for example, can cause false results on some lab tests, including those that measure thyroid hormone levels. For these and other reasons, we always recommend talking with your healthcare provider about vitamins, minerals, and other dietary supplements to help you determine which, if any, may be of value.

Have more questions? See our biotin fact sheet, as well as our fact sheets on other vitamins, minerals, and dietary supplement ingredients.