Noticed faint vertical lines running from the base to the tip of your fingernails as you’ve gotten older? You’re not the only one.

These changes often become more noticeable after age 40. While typically harmless, vertical ridges can sometimes be a sign of underlying health issues. So what causes them—and when should you be concerned?

What Are Vertical Nail Ridges?

Vertical ridges—also known as longitudinal striations—are raised lines that extend from the cuticle to the nail’s edge. Their depth and visibility can differ from person to person and tend to become more prominent with age.

In most cases, these ridges are simply part of the natural aging process. Just as your skin loses elasticity and your hair grays, your nails undergo structural changes as well. Over time, the production of keratin—the protein that makes up your nails—can slow down or become inconsistent, which changes the nail’s surface.

Common Causes of Nail Ridges After 40

1. Aging

The leading cause is aging itself. As you grow older, your body’s ability to regenerate skin cells slows down—including cells in the nail matrix (the area beneath the cuticle where nails begin to form). This slower growth can result in uneven keratin production and, consequently, vertical ridges.

2. Dry Nails

As with aging skin, nails can also dry out more easily over time. A loss of moisture can make nails brittle and highlight natural ridges. Frequent contact with water, soaps, or cleaning agents can worsen this dryness.