Have you noticed thin vertical lines running from the cuticle to the tip of your fingernails as you’ve gotten older? You are not alone. These changes often appear after age 40 and are usually harmless, though in some cases they may point to underlying health issues.

Vertical nail ridges, also known as longitudinal striations, are raised lines that extend along the nail. They can differ in depth and number and often become more visible with age. For most people, this is simply a normal part of aging, similar to how skin loses elasticity or hair turns gray. As the body ages, the production of keratin — the protein that forms nails — may slow down or become uneven, leading to changes in nail texture.

The most common cause is the natural aging process. As cell renewal slows, the nail matrix (the base of the nail) produces keratin less evenly, which can create these ridges. This is a gradual change and typically not a cause for concern.

Another factor is dehydration of the nails. Aging skin and nails tend to become drier, and frequent exposure to water, soaps, and cleaning products can make this worse. Dry nails are more brittle, which can highlight existing ridges and make them more noticeable over time.

Nutritional deficiencies may also play a role. Low levels of important nutrients such as biotin, iron, zinc, or magnesium can weaken nail structure and contribute to ridging. Since the body’s ability to absorb nutrients can decrease with age, these deficiencies may become more common after 40.