Weak or brittle nails are common, especially with aging, frequent hand-washing, or exposure to water and chemicals. But sometimes they can be a clue that something else is going on.
What brittle nails may be telling you
Iron deficiency — Brittle or spoon-shaped nails can sometimes occur with iron-deficiency anemia, particularly when accompanied by fatigue, weakness, or pale skin.
Nutritional deficiencies — Inadequate protein or certain nutrients can affect nail growth, although nail changes alone don’t reliably diagnose a deficiency.
Thyroid problems — Both underactive and overactive thyroid conditions can cause changes in nail growth and texture.
Repeated water or chemical exposure — Frequent soaking, detergents, cleaning products, or nail-polish remover can make nails dry and fragile.
Aging — Nails often become thinner, drier, and more brittle with age.
Fungal infection — Nails that become thick, yellow, crumbly, or distorted may have a fungal infection.
Certain medications or illnesses — Some medical conditions and medications can alter nail growth.
When to get them checked
See a healthcare professional if brittle nails are new, persistent, worsening, or accompanied by fatigue, unexplained weight changes, hair loss, skin changes, or other symptoms. A clinician may recommend blood tests, such as checking iron levels or thyroid function, depending on the situation.
One important point: Don’t automatically assume brittle nails mean you need iron or biotin supplements. Taking supplements unnecessarily can be harmful, and biotin can interfere with some laboratory tests.
