Vertical nail ridges are lines that run from the cuticle to the tip of the nail.
They often become more noticeable after age 40 and are usually harmless.

As the body ages, nail-producing cells slow down, making nails less smooth. Dryness, frequent washing, and exposure to cleaning products can make the ridges appear deeper.

Nutrient deficiencies — such as low biotin, iron, zinc, or magnesium — may also affect nail texture, especially if you’re experiencing fatigue or thinning hair.

In rarer cases, ridges can be linked to circulation problems, thyroid issues, arthritis, or skin conditions.
See a doctor if ridges come with dark streaks, nail splitting, pain, swelling, or sudden changes, as these can signal infection or other concerns.