Ridges in your fingernails are usually caused by normal aging. As you get older, changes in cell turnover within the nail cause vertical lines that run from the cuticle to the tip. These are the most common type of nail ridge and are generally harmless. However, the direction of the ridges matters: vertical ridges are rarely a concern, while horizontal ridges can signal that something disrupted your nail growth and deserve more attention.
Vertical Ridges: Usually Normal
Vertical ridges run lengthwise from the base of your nail to the free edge. Most people start noticing them in their 30s or 40s, and they become more prominent with age. The process is similar to what happens with skin: your body produces less natural oil over time, and the nail plate becomes drier, thinner, and more prone to developing these fine lines.
While aging is the most common explanation, vertical ridges can also appear with very dry skin or eczema, an underactive thyroid (which tends to produce thick, brittle nails alongside the ridging), or iron deficiency. Low iron can also cause nails to become spoon-shaped, curving inward at the center. If your vertical ridges appeared gradually over years and look roughly the same on all your nails, aging is the likely culprit.
Horizontal Ridges: A Sign of Disruption
Horizontal ridges, called Beau’s lines, are dents or grooves that run side to side across the nail. They form when something temporarily stops or slows nail growth at the root. Once growth resumes, a visible indent moves forward as the nail grows out. Because fingernails grow about 3 to 4 millimeters per month, you can sometimes estimate when the disruption happened by measuring how far the ridge is from the cuticle.
Common triggers include:
- Severe illness with high fever, such as COVID-19, pneumonia, or measles
- Physical injury to the nail, like slamming a finger in a door
- Chemotherapy
- Zinc deficiency, which can also cause white spots on nails
- Poor circulation to the hands and feet
- Repeated use of acrylic nails or gel manicures, which can damage the nail over time
A single horizontal ridge on one nail after an injury is nothing to worry about. But Beau’s lines appearing on all your fingernails at the same time suggest a systemic cause, something that affected your whole body at once. People often notice these lines weeks after a major illness and don’t connect the two.
Nutritional Deficiencies That Affect Nails
Several nutrient shortfalls show up in your nails. Iron deficiency is the best known, causing brittle nails with vertical ridging and longitudinal splitting that starts at the tip and works its way back. Zinc deficiency tends to produce horizontal ridges and white spots. Calcium deficiency has been linked to brittle nails with vertical striations. Even protein deficiency and general malnutrition can trigger Beau’s lines.
Vitamin B3 deficiency (pellagra) can also cause horizontal ridges, though this is rare in developed countries. The broader pattern is that nails need a steady supply of nutrients to grow smoothly. Any significant nutritional gap can leave a mark, sometimes literally.
Skin Conditions and Nail Ridging
Your nails grow from the same type of tissue as your skin, so skin conditions often affect nails too. Psoriasis, eczema, lichen planus, and alopecia areata can all produce a rough, ridged nail surface. In more pronounced cases, nails take on a sandpaper-like texture with prominent longitudinal ridging, pitting, splitting, and loss of their normal shine. This can affect a few nails or all of them. Fingernails are more commonly involved than toenails.
If you already have a diagnosed skin condition and notice nail changes, the two are likely connected. If rough, ridged nails appear without an obvious skin condition, it’s worth mentioning to a dermatologist, since nail changes sometimes show up before other symptoms do.
Injury to the Nail Root
The nail matrix, the tissue just beneath your cuticle, is the factory that produces your nail plate. Pinching, crushing, or dropping something heavy on a finger can injure this area and leave behind ridges, dents, or discoloration as the nail grows out. Minor damage usually resolves on its own within a few months as the affected portion of nail grows to the tip and gets trimmed off. More severe or repeated trauma to the matrix can cause permanent ridging on that nail.
Habitual picking or pushing back your cuticles can create the same kind of damage. The cuticle seals the gap between your skin and the nail plate, and repeatedly disrupting it introduces low-grade trauma to the growth zone underneath.
When Ridges Suggest Something Serious
Most nail ridges are benign, but certain changes alongside ridging warrant a closer look. Dark streaks under a nail that are new or changing could indicate melanoma. Nails that curve dramatically downward (called clubbing) can point to lung, heart, or liver disease. Nails that turn half white and half pink may signal kidney problems. Pale nails can reflect anemia, while yellow, thickened nails sometimes indicate lung disease or a fungal infection.
A sudden onset of ridges across multiple nails, especially horizontal ones, is worth bringing up with your doctor. The same goes for ridges accompanied by discoloration, pain, or changes in nail shape.
How to Manage and Prevent Ridges
For age-related vertical ridges, the most effective everyday approach is keeping your nails moisturized. Applying vitamin E oil or coconut oil to your nails and cuticles helps compensate for the decline in natural oil production. Wearing gloves during housework protects nails from hard water and harsh cleaning chemicals that strip moisture.
Gentle buffing can smooth the appearance of vertical ridges, but limit it to once a month and use a fine-grit buffer designed for natural nails, not the coarser ones made for acrylics. File in one direction with light pressure. Over-buffing thins the nail plate and makes the problem worse. Ridge-filling base coats are another option for cosmetically minimizing the lines without removing nail material.
Regular exercise helps too. Cardiovascular activity improves blood flow to your fingers, which supports healthier nail growth. On the other end, long-term use of gel manicures and acrylics takes a toll. Removing gel polish typically requires prolonged soaking in acetone, which dries and weakens nails significantly. Aggressive scraping or filing during removal adds mechanical damage on top of the chemical exposure.
If a nutritional deficiency is behind your ridges, the nails will gradually improve once the deficiency is corrected, though it takes several months to see the change since you’re waiting for an entirely new nail to grow in.