Brittle nails

Brittle nails describe nails that crack, split, peel into layers, flake, or break more easily than they should. In the great majority of cases the cause is external and mechanical rather than a disease: repeated wetting and drying, frequent hand-washing, exposure to detergents, cleaning products, nail polish removers (especially acetone), and cold, dry weather all weaken the nail. Brittle nails also become more common simply with age. Because of this, brittleness on its own — with otherwise healthy-looking nails and no other symptoms — is usually not a sign of anything serious. However, when it is persistent, pronounced, or accompanied by other changes or symptoms, it can occasionally reflect an underlying issue. Iron deficiency can cause brittle, weak nails (and in severe cases, spoon-shaped nails). An underactive thyroid often causes dry, brittle nails alongside tiredness, cold intolerance and dry skin and hair. Less commonly, other nutritional deficiencies or skin and nail conditions contribute. So brittle nails are read in context: usually a cosmetic and lifestyle matter, but occasionally a small clue that fits alongside other findings.

• Everyday wear and moisture — frequent hand-washing, detergents, nail products, dry weather; the commonest cause.
• Ageing — nails naturally become more brittle over time.
• Iron deficiency — can weaken nails, sometimes alongside anaemia.
• Underactive thyroid (hypothyroidism) — dry, brittle nails with other thyroid symptoms.
• Other nutritional factors — occasionally.
• Skin and nail conditions — such as fungal infection or psoriasis affecting the nail.

Brittle nails alone, with no other symptoms, rarely need testing — reducing wet work, protecting the hands and moisturising often help. When brittleness is persistent or comes with other symptoms, a few targeted tests can be worthwhile: iron studies (ferritin and a full blood count) if there is any suggestion of iron deficiency, and thyroid function (TSH) if there are features such as tiredness, cold intolerance or dry skin and hair. The nails themselves are examined for signs of a fungal infection or a skin condition like psoriasis. Mediora.AI can surface an iron or thyroid pattern from your results that might contribute to brittle nails, helping decide whether the nails are simply weathered or part of a wider picture; the interpretation belongs with your doctor.