Myth: Not from calcium deficiency!
Truth: Usually from minor trauma (bumping your nail weeks earlier). Harmless and grow out.
4. YELLOW NAILS
Common cause: Nail polish staining (especially dark reds/browns)
Less common: Fungal infection, psoriasis, or (rarely) lung/thyroid conditions
Try: Take a 2-week polish break. If yellowing persists, see a doctor.
5. SPOON-SHAPED NAILS (KOILONYCHIA)
Nails curve upward like a spoon
Strongly linked to iron-deficiency anemia
Action: Ask your doctor for a ferritin (iron stores) test—even if you don’t feel “anemic”
6. CLUBBING (NAILS CURVE DOWNWARD, FINGERTIPS BULGE)
Can indicate: Low oxygen levels—linked to heart, lung, or liver disease
Not normal: Requires medical evaluation
7. DARK STRIPE (ESPECIALLY BROWN/BLACK)
