Why are my fingernails so brittle?

Updated July 19, 2017

Brittle fingernails, or onychorrhexis, affects about 20 per cent of people and occurs twice as often in women as in men. It can be a sign of an underlying health issue, a result of environmental stressors or due to age. The good news is there are some things people can do to help or reverse this condition.


Fingernails are made up of protein and they can change in colour and growth as a person ages. Nails can become dull and brittle, or yellowed and thickened. As a person gets older, the nail plate loses moisture and natural oils, causing nails to dry out and become more prone to fragmenting and splitting. Changes can also occur as the result of illness, infection or nutrition problems.


People with brittle fingernails often have trouble growing out their nails, as the nails will tend to break when they are brittle. Nails will often also split or peel.

Environmental Causes

Exposure to dry air, particularly in the winter when indoor heat is used and humidity is low, results in dry nails. Long, hot showers or baths also dry out the nails, as well as any prolonged submersion in soapy water, such as when you are doing dishes. Excessive use of nail polish removers, especially those that contain acetone, can cause dry nails.

Health Causes

Brittle fingernails can be a clue to an underlying health issue. Brittle nails can be a sign of hypothyroidism, a condition in which the thyroid gland does not make enough thyroid hormone. A person should visit a doctor if brittle nails are accompanied by other symptoms such as fatigue, unexplained weight gain, constipation, muscle aches or other problems. A doctor can do diagnostic testing to see whether the thyroid is functioning normally. Other health issues that could be causing brittle nails include a skin ailment known as psoriatic arthritis or the liver disease hemochromatosis.


If nails are brittle due to environmental factors, simple steps can keep them healthy and strong. Keep nails dry and clean to prevent bacteria and fungi from growing under the nail. Wear rubber gloves when using soap and water for prolonged periods. Use manicure scissors or clippers to trim the nails and cut them straight across; trimming nails regularly helps strengthen them. Use an emery board instead of a metal nail file; metal files tend to tear nails. Moisturise nails several times a day and after they have been in water. When using nail polish remover, avoid those that contain acetone, which can dry out the nail. According to MedlinePlus, taking the vitamin biotin and using clear nail polish that contains protein can help strengthen nails as well.

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About the Author

Based in New York City, Rebecca Jones has been a writer, reporter and researcher for more than 20 years. Her reporting and researching has helped inform the pages of Glamour, Giant, and Ladies' Home Journal among other publications. In addition to her professional work in the editorial departments of magazines, Jones is an avid poet and as yet unpublished fiction writer.