I've been trying to grow my nails, but they keep splitting and cracking. I try "nail-grow" polishes, but they don't seem to work. What can I do to have longer nails?

— Bess, Iowa

Nails are made of a protein, keratin, so make sure your diet includes an adequate amount of protein. Patients of mine who go on crash diets or make sudden dietary changes often notice that their nails get thinner and brittle. Because nails are not made of calcium, taking calcium supplements and drinking gelatin will not make them grow faster. On the other hand, some research suggests that taking a daily supplement of biotin (a B vitamin) may help strengthen brittle nails. One study showed that taking 2,500 micrograms a day of biotin for two months helped heal dry, splitting nails in two-thirds of the participants.

To prevent splitting in the first place, try to be gentle on your nails. Avoid using your nails to open packages or pop the tops of soda cans. If you do see a split or crack in a nail, resist the urge to peel the nail off; instead, immediately file the ragged edges with a nail file or emery board and buff the surface smooth with a nail buffer. This will prevent the split from getting longer and weakening the nail. Filing your nails into a soft rounded shape (instead of straight across) will also help make them stronger and less likely to split.

Since frequent hand washing can dehydrate the nails and predispose them to splitting, be sure to moisturize your nails after they've been in water. You can use hand cream or cuticle oil. To further protect your nails, wear gloves when you're doing the dishes, gardening, or working with any chemicals or solvents.

If you wear nail polish, avoid acetone-containing polish removers, which can dry out the nail. Instead, look for "acetone free" products. Consider taking a break from nail polish and just buffing your nails for a shiny, natural look.

Many of my patients have also had success with topical nail products containing acetyl mandelic acid. While these products won't make nails grow faster, this alpha hydroxy acid helps smooth out splits on the nail surface, so nails have a chance to grow longer before they break off. Try DermaNail Nail Conditioner or NeoCeuticals Nail Conditioning Solution.

Learn more in the Everyday Health Skin and Beauty Center.