Ever looked at a chipped, brittle, or black-lined nail and wondered why it looks that way? Well, it turns out that nail health is closely associated with how well your body is functioning in other areas.

“For the general population, nail health is most often an indicator of poor nutritional intake or poor digestion,” explains Dr. Sara Norris, a naturopathic doctor based in Los Angeles. “Brittle, weak, and peeling nails are the most common concerns I see in my practice and these symptoms are more often the result of a poor diet than of systemic disease.”

Norris points out that true nail abnormalities generally only involve one or two nails and aren’t related to any major health concerns.

Dr. Mark Benor, clinical assistant professor of family medicine at Keck School of Medicine, agrees: “My job is reassuring people that their nail issues usually don't bespeak a serious underlying illness,” he explains. “The family medicine clinic is full of patients with nail findings of no significance outside of the anxiety they create.”

Healthy nails are considered to be smooth with no discoloration, but if there’s something amiss with the texture and color of yours, we created this guide to keep your nail-related anxieties away.

Brittle

nail health

Rough, splitting nails that may also crack easily are one of the most commonly reported nail problems. They’re also more often seen in women. Officially called onychoschizia, brittle nails are usually caused by repeated wetting and drying of your fingernails, so you should use gloves when getting your hands wet, such as when doing dishes.

The fix: You can try applying lotions that contain alpha-hydroxy acids or lanolin. If this doesn’t work, see a doctor. Norris notes that hypothyroidism can also cause weak, brittle nails, as can iron deficiency.

Soft or weak

nail health

These nails break easily or bend before snapping. Soft nails might be caused by overexposure to moisture or chemicals — think detergent, cleaning fluids, nail treatments, and nail polish remover.

The fix: Avoid having chemicals around your nails. Go natural to give your nails a chance to recover. Weak nails are most likely associated with a deficiency in B vitamins, calcium, iron, or fatty acids. Norris explains that it’s best not to take iron as a supplement unless you know you’re deficient. Instead, start taking a multivitamin that includes calcium and B vitamins.

Peeling

nail health

This is likely caused by external trauma to the nail itself — by using your nail as a tool, pressing into the nail too firmly or removing acrylic nail polish. Nails can also peel if you soak your hands too long in sudsy water.

Here’s a trick to figuring out whether it’s an internal or external cause: Are your toenails also peeling? If so, it might be an internal cause, such as iron deficiency; if not, it’s probably external.

The fix: If you think it’s internal, add iron to your diet with lentils, red meat, fortified cereal, or baked potato skins. You can also take biotin. If the cause is external, keep your nails moisturized by applying lotion after any activity that might dry them out. You can also wear protective gloves while doing the dishes.

Ridges

nail health

Have you ever noticed ridges that look like little horizontal or vertical waves on your fingernails? Vertical ridges generally appear later in life and run from the tip of your fingernail to the cuticle. As long as they aren’t accompanied by other symptoms such as changes in color, they’re considered benign. On the other hand, horizontal ridges, also called Beau’s lines, are a sign of a more serious symptom.

The fix: See a doctor to find the underlying cause. Vertical ridges could be indicative of iron deficiency anemia while horizontal lines could point to an underlying condition such as kidney disease, which can actually stop nail growth until the problem has been treated.

Yellow

nail health

Yellow nails are, believe it or not, relatively common, and usually caused by one of two factors: an infection or a reaction from a product you’ve been using, such as nail polish.

The fix: Your new nails should grow in clear again, but there are many natural treatments such as tea tree oil or vitamin E to help tackle infections. A multivitamin might also help with this.

You can try these before consulting a doctor, but if the color remains, it might be a sign of a larger issue.

Black lines

nail health

Also called a splinter hemorrhage, black lines (which can appear brown or dark red) look like splinters. They can appear multiple times. The most likely cause is a trauma to your nail, such as accidentally slamming a door on your finger.

The fix: The line is the result of blood vessel inflammation under your nail and should disappear over time as your nail grows.

White spots

nail health

“Scattered white spots on the nails, which usually start appearing around middle school age, can signify a zinc deficiency,” explains Norris. “Usually 30 milligrams per day of zinc for three months will alleviate it.” Other possible causes include:

  • an allergic reaction
  • a fungal infection
  • injury to your nail

No half-moons

nail health

You know those little rounded white curves at the base of your fingernail? Those are called fingernail moons, based on the Latin word lunula (little moons! So sweet!). But not everyone has them. What does it mean if you don’t? Most of the time, this means nothing and they could just be hidden under your skin. If they seem to have disappeared, it could be a sign of:

But you should see a doctor if they start turning red and you experience:

  • dizziness
  • anxiety
  • lightheadedness
  • weight loss or gain
  • unusual cravings

“The most common systemic conditions I see in my practice are psoriasis, which typically will cause pitting of the nails, and hypothyroidism which can cause weak, brittle nails,” explains Norris.

Growths around the base of the nail or other changes should be reported to your doctor. According to Norris, more concerning signs of disease of a nail include the following:

  • pitting
  • ridging
  • discoloration
  • longitudinal and transverse grooving
  • changes in thickness and surface texture
Nail healthPossible causeAdditional symptoms to look out for
brittlehypothyroidism, iron deficiencyfatigue, weight loss, anxiety
soft or weakoverexposure to moisture or chemicalsfatigue, weakness
yellowthyroid conditions, psoriasis, or diabetesfatigue, anxiety, inflamed skin, excessive thirst
black linespsoriasis, endocarditis, nail melanomainflamed skin, heart murmur, night sweats, nail bleeding
ridgesiron deficiency anemia (vertical) or kidney disease (horizontal) anxiety, weight loss, swelling feet, excessive urine; horizontal ridges on all twenty toes can be a sign of mumps, thyroid disease, or diabetes
no half-moonsanemia, malnutrition, or depressionfatigue, weight loss, dizziness, unusual cravings, poor eyesight
peeling iron deficiencyfatigue, paleness, heart palpitations

“Our bodies are smart so when we’re low in vitamins and minerals, our nails and hair will show it,” explains Norris.

Eating a variety of whole foods will usually get you all the vitamins, minerals, and nutrients your nails need. A simple fix is to start taking a quality multivitamin, but Norris advises against a one-a-day type: “It's difficult for our bodies to digest large compressed tablets. When taking these products, we don't actually break it down effectively so we miss out on the vitamins and minerals that are within it.”

Instead, she suggests looking for a product that comes in easy-to-digest capsules. Why? Capsules are typically made from gelatin and it's much easier for our bodies to break down gelatin to get to the vitamins and minerals within the product.

Opt for popular choices: biotin and the herb horsetail. That said, if you begin taking biotin for nail health, Norris advises to discontinue use two weeks prior to having any lab work. There’s new research showing that biotin may interfere with lab results including thyroid labs and markers to assess for heart attacks.

Overall, if your nails are acting up on their own, without any additional symptoms, it’s usually not a cause for concern.


Abigail Rasminsky has written for the New York Times, O: The Oprah Magazine, The Cut, Lenny Letter, Longreads, and The Washington Post, among other publications. A graduate of Columbia’s MFA program, she lives in Los Angeles with her family. You can find her on her website and on Twitter.