Why Do White Spots Appear on Nails? Doctors Explain the Real Cause
Many people blame calcium deficiency for white marks on their nails, but doctors say the most common cause is far simpler and usually harmless.
Illustration: AI-generated image
If you've ever spotted small white marks on your fingernails, you've probably heard the old wives' tale: it's a sign you need more calcium. But according to medical experts, the real cause is usually far less concerning—and much simpler.
The most common culprit: minor injuries
Known medically as leukonychia, white spots on nails are most often the result of tiny injuries to the nail or its root (the matrix). "You might not even remember bumping your nail, because it can take up to six weeks for the damage to show up," explain experts from the University of Cambridge's Naked Scientists. By the time the spot appears, the original knock has long been forgotten. Common triggers include hitting your nail against a hard surface, biting your nails, wearing tight shoes, or even over-zealous manicuring.
Is it really a calcium deficiency?
Despite the popular belief, there's no solid evidence linking white spots to low calcium levels. BBC Science Focus notes that irregular white dots are typically due to minor trauma, while white lines on nails may indicate severe malnutrition or low blood protein—but not calcium. Cleveland Clinic adds that while some experts suspect iron, calcium or zinc deficiencies might play a role, the research isn't conclusive. Cambridge scientists, however, state that calcium does not affect nail appearance, though low iron can cause spoon-shaped nails and zinc deficiency may lead to brittle nails and white spots.
Other possible causes
Though rare, white spots can sometimes be linked to other factors. According to Cleveland Clinic, these may include:
- Allergic reactions to nail polish, hardeners, polish removers or artificial nails
- Exposure to heavy metals like arsenic or lead
- Certain medications, such as sulfonamides used to treat bacterial infections
In even rarer cases, white spots may be associated with systemic conditions like diabetes, heart failure, HIV, liver cirrhosis or psoriasis, but that's not typical.
When to see a doctor
If your white spots are from a minor injury, no treatment is needed—they'll grow out over time. On fingernails, that can take six to nine months; on toenails, up to 12 to 18 months. To reduce the chance of spots, wear protective gloves during rough tasks, choose comfortable shoes, keep nails short and moisturised, and avoid harsh chemicals. However, seek medical advice if you notice new nail changes like increased brittleness, colour changes, pitting or ridges, especially if accompanied by symptoms such as fatigue, weakness, blurred vision, confusion or shortness of breath.
