Have you ever taken off your nail polish only to notice a dark line on the nail ... Most of the time, thin, vertical black ...

Nails can say a lot about your overall health. Symptoms like dry or yellow nails, white spots, and dark lines ... Horizontal or Vertical Ridges Some people may have lines running up and down ...

While brittle nails can be caused by dehydration or overexposure to chemicals, if they accompany other symptoms, it could indicate a deficiency. You might also notice dark lines or streaks under ...