Fingernail Health Can Hold Clues to Internal Health. What Do Yours Say?

Don Colbert, MD — Wed, 21 Feb 2024 19:14:08 +0000

Written by Don Colbert, MD, board-certified in family practice and in anti-aging and integrative medicine for more than 25 years
Last reviewed and updated: October 17, 2026

Is it possible that your fingernails hold the secrets to your health? Can they show you nutrition deficiencies, underlying systemic issues, injuries, or toxic loads from medications? Amazingly, they hold clues into the mysteries that make up your overall health. While your fingernail health is not a stand-alone diagnostic tool, it can help you recognize potential issues that can be further investigated.

What do your nails say about your overall health? Find out today!

What Fingernail Health Says About Your Overall Health

1. Soft or Weak Nails

Soft or weak nails often bend before snapping. Like brittle nails, soft nails may be a fingernail health sign that points to overexposure to moisture or chemicals like detergent, cleaning fluids, nail treatments, and nail polish remover.

However, weak nails may also be associated with a deficiency in B vitamins, calcium, iron, or fatty acids. Other signs of vitamin B deficiency include pins and needles tingling in hands and/or feet, fatigue, pale skin, fast heart rate, mouth pain or swelling, red smooth tongue, and/or depressed moods or mental health changes (1, 2, 3).

How can you improve fingernail health when they are soft and weak? Reduce the amount of chemical exposure to your nails. Give your nails a break from polish and/or remover. If other signs point to vitamin and mineral deficiencies, try to increase your intake.

2. Pitted Nails

When you look at your nails, do you see evidence of pitting? Nail pits are small round depressions or notches that appear in the nails. Nail pitting is common in those with skin conditions including psoriasis and eczema. It can coexist with psoriatic arthritis, or may be related to alopecia areata, an autoimmune disease that causes hair loss (4).

How can you improve fingernail health if you see nail pitting? If you see nail pitting, it’s worthwhile to talk to your medical provider. Often, this is associated with inflammation or disorders of other connective tissue including skin and joints. You may talk about ways to decrease overall inflammation while supporting connective tissue health.

3. Peeling Fingernails

Peeling fingernails can be tricky. It is often due to external trauma. However, it can also be caused by having a low iron status internally. So, which is it for you?

One way to figure it out is to look at your toenails. If they are peeling as well, it’s more likely to be an internal, possibly iron, issue.

Other iron deficiency symptoms include unexplained fatigue, dark undereye circles, spooned nails (see below), heavy, rather than springy, legs when you walk or run, or newly formed paleness. Iron-deficiency can be assessed and diagnosed with laboratory tests including serum ferritin (5).

How can you improve fingernail health when they are peeling? If caused by external trauma, refrain from using your fingernails as a tool, pressing into the nail too firmly, or using acrylic polish on nails. If caused by iron deficiency, talk to your medical provider about testing serum ferritin levels and/or adding iron-rich foods or supplements.

4. Brittle Nails

If your fingernails are rough or splitting, you may have what’s called onychoschizia. It’s actually quite common. Typically, it does NOT point to an internal health problem, but a drying out due to repeatedly wetting and drying your hands and nails, such as when washing hands, doing dishes, etc.

How can you improve fingernail health when they are brittle? Try using hydrating lotions on your hands and nails to protect them from wetting and drying. Consider wearing gloves while washing dishes or doing other water-heavy tasks.

5. Fingernail Ridges

Do you have thin vertical ridges that run from the tip of your fingernail down to your cuticle? If so, don’t fret, these are usually not a cause for concern or an indication of a health issue. If you have horizontal ridges, they may or may not be a sign of a health condition or a side effect of treatment. For example, horizontal grooves called Beau’s lines can appear after chemotherapy and may show up across all 20 nails in step with each round of treatment. Beau’s lines have also been associated with a high fever or serious illness such as measles, mumps, malaria, typhoid fever, scarlet fever, and hand, foot, and mouth disease. In these cases, people are usually diagnosed with the illness first and notice the ridges weeks later as the nail grows out (6).

How can you improve fingernail health when you notice ridges? If you notice vertical ridges, you can ignore them or gently buff the surface of your nail with a fingernail buffer to smooth them. If you notice horizontal lines, you may attribute it to a known medication or medical issue, or you can see a healthcare professional to find the underlying cause.

6. Thick Yellow Nails

Yellow nails are actually relatively common. They can be caused by an infection or a reaction to a product, such as nail polish. Yellow, thick nails are a different issue. If you notice your fingernails or toenails are thick, peeling, and discolored, it could be a nail fungal infection, known as onychomycosis (7).

In rare cases, yellow nails can indicate a thyroid condition, skin conditions, or blood sugar abnormalities.

How can you improve fingernail health when they are yellowing and/or thick? Suspect a nail product as the culprit? Discontinue use and monitor changes. If not thickening, but also not due to a product, talk to your medical professional about potential causes. If your nails are thickening and yellowing, talk to your medical professional about possible fungal infection and treatment.

7. Black Lines on Nails

Thin dark lines under the nail are often splinter hemorrhages, which are tiny areas of bleeding beneath the nail. These lines, which can appear black, brown, or dark red, run in the direction the nail grows and look like small splinters, and there may be more than one. Most of the time, they are caused by minor trauma to the nail. As the nail grows out, they should disappear if due to injury.

When they don’t, and in rare cases, the lines can be a sign of an underlying issue such as psoriasis or an infection of the heart valves (endocarditis). A different finding, a wide brown or black stripe that runs the full length of the nail, especially on a single nail, should always be checked by a doctor, because it can occasionally be a sign of melanoma under the nail (8).

How can you improve fingernail health if you see black lines on them? If from trauma, give it time. The lines should disappear as your nail grows out. If there’s no change over a few weeks, talk to your healthcare professional and monitor any other symptoms, such as inflamed skin, night sweats, or bleeding in the nail.

8. Nails with White Spots

If you see scattered white spots on your nails, the most common cause is minor injury to the nail, such as bumping it or pushing back the cuticles too hard. White spots may also come from an allergic reaction to a product or a fungal infection (see thick yellow nails), and they have sometimes been linked to zinc deficiency.

Other signs of zinc deficiency include unexplained weight loss, wounds that won’t heal, lack of alertness, decreased sense of smell and taste, diarrhea, loss of appetite, and/or open sores on the skin.

How can you improve fingernail health if you see white spots? First, give your nails a break from polish or other products and allow the nail to grow. If the spots remain or reappear, or you have other signs of low zinc status, talk with your healthcare professional about possible zinc deficiency and supplementation.

9. Spooned Nails

Spoon nails are soft nails turned up around the edges, creating “spoons.” This condition is also called koilonychia, and it is often a symptom of iron deficiency anemia. Iron deficiency anemia can be caused by inadequate iron intake or absorption, bleeding, gastrointestinal disorders, and more.

As mentioned above, other iron deficiency symptoms include unexplained fatigue, dark undereye circles, peeling nails (see above), heavy, rather than springy, legs when you walk or run, or newly formed paleness. Iron-deficiency can be assessed and diagnosed with laboratory tests including serum ferritin (9).

How can you improve spooned fingernail health? Since this is often caused by iron deficiency, talk to your medical provider about testing serum ferritin levels and/or adding iron-rich foods or supplements.

Watch: Collagen Support for Skin, Hair, and Nails

In this short clip, I introduce the vanilla collagen powder I formulated, which combines Type I, II, and III collagen from marine and chicken sources to support healthy skin, hair, nails, and joints.

General Recommendations to Take Care of Fingernail Health

Fingernails are an epithelial skin appendage. They are made of a hardened nail plate surrounded by specialized epithelial surfaces. The nail plate (the portion of the nail you see on top) is formed of keratinised epithelial cells. Fingernails are incredibly dynamic and grow outward at an average rate of about 3 millimeters per month, so a fingernail takes roughly 4 to 6 months to grow out completely.

As described above, fingernails can display signs of connective tissue health, nutrient deficiencies, and systemic issues. It stands to reason then, to support connective tissue health and adequate nutrient intake. From there, if your fingernails still show abnormalities, you may find evidence of other underlying or systemic conditions.

To take care of fingernail health in terms of connective tissue support, reduce inflammation, and adequate nutrient intake, consider adding:

In addition, consider giving your nails regular breaks from harsh polishes, glues, and other chemical agents that may harm them.

Bottom Line

Your fingernail health may hold clues to your internal health. While they are not a stand-alone diagnostic tool, they can be the first indication of an issue. Take care of your fingernails and monitor any signs or symptoms of abnormalities. What are your fingernails telling you? If you notice a change that does not grow out, or one that comes with other symptoms, see your doctor.

Frequently Asked Questions

What can your fingernails tell you about your health?

Your nails can show signs of nutrient shortages such as low iron, skin conditions such as psoriasis, fungal infections, and the effects of illness or medication. They are not a diagnostic tool on their own, but a change that lasts is worth mentioning to your doctor.

What vitamin deficiency causes ridges in fingernails?

Vertical ridges are usually a normal part of aging and are not caused by a deficiency. Horizontal ridges (Beau’s lines) usually follow a serious illness, a high fever, or chemotherapy. Brittle, soft, or spoon-shaped nails are more often linked to low iron, so ask your doctor about checking your ferritin level.

What do white spots on fingernails mean?

Most white spots come from minor bumps to the nail and grow out over a few months. Less often, they are linked to a fungal infection, a reaction to nail products, or low zinc.

Can low iron cause nail problems?

Yes. Iron deficiency can cause brittle, peeling, or spoon-shaped (koilonychia) nails. A simple blood test that includes serum ferritin can show whether your iron stores are low. Do not start high-dose iron without testing, because too much iron can be harmful.

When should I see a doctor about my nails?

See your doctor if you notice a dark stripe running the length of a nail, a change that does not grow out, a nail lifting away from the skin, swelling or pain around the nail, or nail changes along with fatigue, weight loss, or shortness of breath.

How long does it take for a fingernail to grow out?

Fingernails grow about 3 millimeters a month, so a full fingernail takes roughly 4 to 6 months to replace itself. Toenails grow more slowly and can take a year or longer. That is why improvements from better nutrition take time to show in your nails.

References

This article is for educational purposes only and is not medical advice. Talk with your own doctor before changing your diet, starting a supplement, or changing any medication. These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease.

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