Most nail ridges are vertical lines running from the cuticle to the tip, and they’re a normal part of aging that you can minimize but not eliminate entirely. The key to smoother nails is understanding which type of ridges you have, addressing any underlying cause, and adopting habits that support healthy nail growth. Since fingernails grow about 3.5 millimeters per month, any improvement takes three to six months to fully show.
Vertical vs. Horizontal Ridges
The first step is figuring out which direction your ridges run, because the causes and solutions differ completely.
Vertical ridges are lines that go lengthwise from your cuticle to the tip. They become more noticeable with age as the rate of cell turnover in the nail matrix changes. Dry skin, eczema, thyroid problems, and iron deficiency can all make them worse. These ridges are almost always harmless.
Horizontal ridges, called Beau’s lines, are dents or grooves that run side to side across the nail. They form when something disrupts nail growth: a high fever, a serious illness like pneumonia or COVID-19, severe emotional stress, a nutritional deficiency, or physical trauma like slamming your finger in a door. Chronic conditions such as diabetes, peripheral artery disease, and hypothyroidism can also cause them. If you suddenly notice horizontal ridges on multiple nails, that points to a systemic issue rather than a local injury.
Rule Out Nutritional Deficiencies
Several nutrient gaps directly contribute to nail ridging. Iron deficiency can cause vertical ridging, brittleness, and even spoon-shaped nails. Zinc deficiency is linked to both horizontal ridges and white spots. Low protein intake and severe calcium deficiency are associated with ridging and splitting as well.
If your diet is low in red meat, legumes, leafy greens, or seafood, those are the nutrients most likely to be falling short. A simple blood test can confirm whether iron or zinc levels are the issue. Correcting a true deficiency often improves nail texture within a few growth cycles, though it takes patience since each nail needs roughly four to six months to fully replace itself.
What Biotin Can (and Can’t) Do
Biotin is the most widely marketed supplement for nails, and there is some evidence behind it. In one study, 2.5 mg of biotin daily for an average of 5.5 months resulted in firmer, harder nails in 91% of patients who had thin, brittle nails. Another small study found nail thickness increased by 25% during supplementation. Those numbers are promising, but the studies were small and focused on people with already brittle nails. If your nails are generally healthy with mild age-related ridges, biotin is less likely to make a dramatic difference.
There’s no harm in trying it for several months to see if your nails improve. Just know that biotin addresses brittleness and thickness more than it erases visible ridges.
Daily Habits That Protect Your Nails
Much of what makes ridges worse is repetitive, low-grade damage to the nail and cuticle. Habits like nail biting, cuticle picking, and aggressive manicures disrupt the nail matrix, which is the tissue under the cuticle where new nail cells form. Repetitively picking at a thumb’s cuticle with your index finger, for example, can create a distinct line of horizontal hatch marks down the center of the nail.
Long-term use of acrylic nails and gel manicures is another common culprit. The application and removal process physically damages the nail plate over time, leading to ridging and thinning. If you wear these regularly and notice worsening ridges, taking a break for several months gives nails a chance to recover.
A few straightforward protective habits help:
- Keep nails trimmed. Shorter nails are less prone to catching, bending, and cracking, all of which stress the nail bed.
- Moisturize your cuticles. Dry, cracked cuticles let damage reach the nail matrix. A simple cuticle oil or even plain petroleum jelly applied nightly keeps them pliable.
- Wear gloves for wet work. Repeated soaking in water and exposure to cleaning chemicals strips oils from the nail plate, making ridges more visible and nails more brittle.
- Wear properly fitting shoes. Tight shoes cause repeated toenail trauma that leads to ridging and thickening over time.
Smoothing Ridges Cosmetically
While you work on improving nail health from the inside, you can reduce the appearance of ridges at the surface. A fine-grit nail buffer (look for 240 grit or higher) can gently smooth out minor vertical ridges. Buff lightly and in one direction only. Overbuffing thins the nail plate and makes it weaker, so limit this to once every couple of weeks.
Ridge-filling base coats are another option. These are slightly thicker than regular base coats and fill in the grooves, creating a smoother surface for polish or on their own. They won’t fix ridges, but they mask them effectively.
How Long Results Take
Fingernails grow at about 3.5 mm per month. A full fingernail takes roughly four to six months to grow from cuticle to tip. That means if you correct a deficiency, stop a damaging habit, or recover from an illness today, the smooth new nail won’t fully replace the ridged portion for half a year. Toenails are slower, often taking 12 to 18 months.
Vertical ridges from aging will keep reappearing because the underlying change in the nail matrix is ongoing. You can minimize their severity through good nutrition and hydration, but some degree of ridging with age is normal and not a sign of any health problem.
When Ridges Signal Something Bigger
Ridges alone are rarely cause for alarm, but certain nail changes alongside ridges deserve attention. Nails that curve dramatically around the fingertips (clubbing) can indicate lung or heart problems. Nails that turn mostly white with a thin pink band at the tip can be linked to liver disease or diabetes. Spoon-shaped nails that curve upward at the edges are a classic sign of iron deficiency anemia. Small round pits scattered across the nail surface are common in psoriasis.
Horizontal ridges appearing suddenly on several nails at once suggest your body went through a significant stress, whether illness, nutritional crisis, or emotional trauma, a few months prior. If you can’t identify an obvious cause, it’s worth getting bloodwork to check thyroid function, iron, and zinc levels.