Noticing thin vertical lines on your fingernails as you get older is very common, especially after 40. These vertical ridges, known as longitudinal striations, usually form as part of natural aging, when nail growth slows and keratin is produced less evenly. Dryness from frequent handwashing or chemical exposure can make them more visible, and in some cases they may be linked to mild nutritional deficiencies like low biotin, iron, zinc, or magnesium. Most of the time they’re harmless, but paying attention to overall nail health can help rule out underlying issues.
