The Nutrient That Saves Your Nails

It’s summer, and your fingernails are growing faster than the weeds in your zucchini patch (yes, fingernails do grow faster in the summer). But that doesn’t automatically mean they’re growing better. If you’re looking around for something to stop the splitting, breaking, and peeling, consider the only nutritional supplement that has gotten a universal thumbs-up from science: biotin.

Biotin, a B-complex vitamin, has long been used to treat damaged hooves on horses. And because our nails are made of the same stuff (keratin), it turns out the vitamin works for us two-legged creatures, too.

How much do you need? Well, that’s where it gets a little tricky. When dermatologists first put biotin to the test in humans nearly 20 years ago, they found that extra biotin intake could increase nail thickness up to 25 percent in women who had soft or brittle nails. One study used 2.5 milligrams of biotin daily. That’s a lot, especially considering that standard servings of biotin-rich foods -- peanuts, filberts, cashews, almonds, soybeans, eggs, tomatoes, sweet potatoes, chard, carrots, haddock, salmon -- dole out this nutrient in doses generally under 10 micrograms at a time. We recommend getting 300 micrograms of biotin each day. Talk to your doc if you’re going to go higher than that.

What your nails don’t need: Extra protein or gelatin won’t do anything for your nails. But polish removers containing acetone will -- it can leave nails drier than the best of Stephen Colbert’s humor.