As a cosmetic dermatologist, there is a group of questions I get asked almost every day. Many are about the little things that bother people every day. Some are unavoidable facts of life. Some are brought on or made worse by daily activities or beauty treatments. Some, such as nail problems, are both.

Q. Why do my nails split?

A. Nails split when they are dehydrated from solvents, hand washing, dry weather and aging. Wear gloves when cleaning or doing dishes. Use an acetone free polish remover. Oval shaped nails chip more easily. Trim nails relatively short with a minimal arc. File in one direction. Apply nail oil or a heavy moisturizer to the nail plate, free edge and cuticle before bed.

Q. Do those vitamin pills for nails really help?

A. Nail supplements are combinations of vitamins, amino acids, and minerals. The efficacy of most is unproven. Nutritional deficiency of Vitamin A, iron, selenium or zinc can result in fragile, misshapen or discolored nails and correcting the deficiency may lead to improvement. Increasing the amount of dietary iron can lead to some improvement in brittle nails, even though laboratory iron levels are within the normal range. Do not take iron supplements without physician supervision, as this can cause serious problems.

Studies show daily treatment with 2.5 mg (2500mcg) of biotin and 10 mg (10,000mcg) of bioavailable silicon improves nail thickness, enhances nail growth and decreases peeling and splitting.

Q. Do those paint on nail strengtheners really help?

A. Nail strengtheners are applied as a base coat or cream and give temporary improvement by mechanically protecting the nail plate and cross-linking keratin.

The problem is that they can actually cause nails to be more brittle because of reduced flexibility despite increased strength. Formaldehyde nail strengtheners give the strongest but most brittle nails, and can cause contact dermatitis and lifting of the nail from the nail bed. Dimethyl urea does not penetrate as deeply as formaldehyde, so nails are not as strong, but also less brittle. It has less potential for allergic sensitization, but it does occur.