What Do Your Nails Say About Your Health?

Farzollah Gholizadeh and Fariba Bayrami

Signs you shouldn’t ignore

Have you ever looked carefully at your nails for a few seconds before cutting them?

What colour are your nails?
Are they smooth, or do they have ridges?
Are they strong, or do they break easily?
How much of the white half-moon (lunula) at the base of the nail can you see?
Do your nails grow quickly or slowly?
Has a spot, small pit or change in colour appeared that wasn’t there before?

Nails are not just part of how our hands and feet look. They are slow-growing tissues, so they can sometimes carry traces of the body’s state from weeks or even months earlier.

In Avicennian–Greek medicine and other schools of traditional medicine, observing the body’s outward appearance has been an important way of understanding a person’s inner state. The colour, texture, shape and quality of the nails were considered together with the skin, tongue, hair, eyes, pulse and other signs.

Modern medicine also takes nail changes into account in many skin diseases and in some general disorders of the body.

But the important point is this:

The nail does not diagnose disease on its own; the nail gives clues.

The art of assessment is understanding these clues and weighing them together with the body’s other signs.

Why can nails tell us about the body?

The nail plate is made largely of keratin and grows from the nail matrix (the nail root).

Normal nail growth depends on many factors, including:

• Adequate, balanced nutrition
• Blood circulation
• Oxygenation
• The health of the tissue around the nail
• The body’s general condition
• Age
• Hormones
• Illnesses
• Medicines
• Environmental and chemical factors

So changes in the body’s condition can sometimes show in the nail’s colour, growth rate, thickness, strength or shape .

A nail is not like a blood test that gives a precise number; it is more like a slow-moving logbook that records some of the body’s changes over time.

What does a healthy nail usually look like?

A healthy nail usually has a fairly smooth surface, a suitable texture and a colour in keeping with the natural colour of the skin and nail bed.

It should not be very brittle, constantly peel in layers or lift from its bed for no reason.

Of course, the shape and thickness of the nail, and even how much of the half-moon (lunula) shows, vary from person to person.

So there is a very important principle in reading signs:

A change compared with a person’s own normal is usually more important than comparing their nails with other people’s.

If someone has had nails of a particular shape for years, that is not necessarily a sign of illness. But if the same nails change noticeably within a few months, it is worth looking into more closely.

The first thing the nail shows us: colour

One of the first steps in observing the nails is looking at their colour.

A nail can look whiter, paler, yellower, bluer or more purple than before, it can darken, or coloured lines and spots can appear on it.

Each of these changes can have many causes.

For example, a noticeably paler nail bed, together with other signs, can sometimes draw our attention to the state of the blood.

Yellowing of the nails can have various causes, from dyes and external substances to fungal infection and some illnesses.

Nails turning unusually blue or purple can draw attention to oxygenation and circulation.

But none of these colours is a definite diagnosis on its own.

Colour is the start of the questions, not the end of the diagnosis.

White spots: not always a calcium deficiency

One of the most common beliefs is that every white spot on a nail means a calcium deficiency.

This explanation is an oversimplification.

White spots can result from small knocks to the area where the nail forms, and they can have other causes too.

What matters is the type of spot, how many there are, where they are, whether they keep coming back, whether there are other changes in the nail, and the person’s general condition.

A more thorough assessment also looks at nutritional status, absorption of nutrients and certain micronutrients; but a deficiency of a specific nutrient cannot be diagnosed from a single white dot.

What do brittle nails tell us?

Brittle nails are one of the most common complaints.

Sometimes the cause is very simple:

Frequent contact with water, detergents, solvents and products such as nail polish and acetone, frequent manicures, knocks or dry surroundings.

But if the brittleness is severe and constant, a bigger picture needs to be looked at.

Nutritional status, iron and other nutrients, thyroid problems, skin diseases and the person’s general condition may be considered in the assessment.

From a traditional medicine point of view too, the quality and strength of the nail, together with other signs, help assess how well the tissues are nourished and the body’s balance of moisture and dryness.

Nail ridges: lines that sometimes record the body’s history

Some vertical lines can be normal, especially with age.

But not all ridges are the same.

Sometimes clear horizontal lines appear on several nails. Changes like these can show that the nail’s normal growth was disrupted for a time.

This disruption may have followed a serious illness, a fever, significant physical stress or other situations.

Interestingly, because the nail grows slowly, the position of the line on the nail can sometimes give a specialist a clue about roughly when the disruption happened .

So the nail sometimes carries part of the body’s past.

Small pits in the nail

Sometimes the surface of the nail looks as if lots of tiny dots have been pressed into it.

This can be seen in some skin conditions and inflammatory diseases.

The important thing is this: a proper assessment doesn’t look only at the pits themselves; the skin, hair, joints, the number of affected nails and other symptoms should also be examined.

A single sign usually has limited meaning.

When the shape of the nail changes

Sometimes the problem is not just colour or brittleness; the overall shape of the nail changes.

A nail can become very domed, dip like a spoon, thicken, lift from its bed, or its curve can change noticeably compared with before.

These changes matter more especially when:

they are new, they affect several nails at once, or they come with other general symptoms.

Some changes in nail shape can draw a practitioner’s attention to the state of the blood, lungs, heart, thyroid or nutrition, or to skin diseases.

But it is exactly here that simple observation should give way to interpreting patterns .

Nails and anaemia

Some nail changes, together with other signs, can lead us to check iron and the blood.

For example, if a change in nail shape or brittleness comes with pallor, tiredness, weakness, dizziness, palpitations or reduced capacity for exertion, checking for anaemia becomes more important.

The important thing is this: anaemia is not diagnosed by looking at the nails; the nails can only be one of the clues.

Nails and the thyroid

Thyroid disorders can also affect the skin, hair and nails.

A change in growth rate, brittleness, a change in nail quality or the nail lifting from its bed can in some cases occur together with thyroid disorders.

If nail changes appear at the same time as changes in weight, tolerance of cold or heat, heartbeat, energy, sweating, skin and hair, they are even more worth looking into.

The same principle applies again:

The nail should be read together with the body, not apart from it.

Nails and diabetes

In people with diabetes, many factors can affect the nails and the tissue around them.

Changes in peripheral circulation, a greater tendency to certain infections and impaired tissue repair are among the factors that make nail care — especially toenail care — more important.

In a person with diabetes, discoloured or thickened nails, fungal infection or damage around the nail should be looked at more carefully.

Nails, liver and kidneys

Some systemic diseases can also cause changes in how the nails look.

Certain patterns of colour or appearance change have been reported in some liver and kidney diseases.

But these signs only gain real value when they come with changes in the colour of the skin and eyes, swelling, itching, changes in urine, general weakness or other symptoms.

So seeing a nail of a different colour never on its own means a diagnosis of liver or kidney disease.

Nails, heart and lungs

Some important changes in nail colour and shape can draw attention to oxygenation, the heart and the lungs.

For example, a nail bed that has recently turned blue or purple, or a marked, gradual change in the shape of the fingertips and nails, is not something that can be explained by temperament alone.

A medical assessment is important, especially if it comes with shortness of breath, weakness or reduced capacity for exertion.

Nails, the digestive system and nutrient absorption

One of the important principles of Avicennian–Greek medicine is that the quality of the body’s tissues depends largely on the quality of digestion and nourishment.

The nails are no exception.

If the digestive system can’t digest and absorb nutrients properly, the skin, hair and nails can be affected over time.

In modern medicine too, some digestive disorders and absorption problems can occur together with deficiencies of iron, zinc, vitamins or other nutrients, and can affect the nails indirectly.

So to understand the cause of a nail change, we sometimes need to take the question beyond the nail:

How is digestion?
How is appetite?
How are the bowels?
Are there signs of weight loss or poor absorption?

How fast nails grow is a sign too

Nails grow at a certain rate, but this rate isn’t the same for everyone.

Age, season, nutritional status, general health, illness and many other factors affect this rate.

So slower or noticeably changed nail growth can be part of a bigger picture, especially if it comes with other changes in the body.

Sometimes what matters is not whether growth is “slow or fast”, but a change compared with the usual growth rate of the person’s own nails.

What does the white half-moon at the base of the nail tell us?

The pale, crescent-shaped area at the base of some nails, called the lunula or nail half-moon , is a natural part of the nail’s structure.

Its size and how much of it shows vary from person to person, and even between the fingers of the same person.

So a small or large half-moon should not on its own be used to diagnose illness.

In traditional sign-reading, however, the half-moon, the colour of the nail bed, the quality of growth and the nail’s other features are observed together.

Its diagnostic value increases when several consistent changes appear at the same time .

Can temperament be seen in the quality of the nails?

In Avicennian–Greek medicine, assessing temperament never relies on a single organ.

Still, the quality of the nails can be part of the overall set of signs.

In general, more dryness, brittleness and roughness, together with other signs, can point to increased dryness in the body.

The quality of the tissue, growth, colour and the state of the nail bed should be assessed together with the skin, hair, build, body temperature, sleep, digestion, pulse and other signs.

So you cannot say for certain that someone is sanguine, choleric, phlegmatic or melancholic just by looking at their nails.

Assessing temperament means identifying a pattern, not a single sign.

Which matter more: fingernails or toenails?

Both matter, but their conditions are different.

Toenails are affected more by shoes, pressure, knocks, moisture and fungal infection.

Fingernails are exposed more to water, detergents, chemicals, manicures, polish, gel and everyday damage.

So before linking any nail change to an internal illness, local factors need to be ruled out.

Has one nail changed, or all of them?

This is a very important question.

If only one nail has changed, local factors such as a knock, infection or damage become more likely.

If several nails at once show a similar change, paying attention to general factors in the body becomes more important.

This rule is not absolute, but it is one of the simplest principles for starting to observe nails properly.

A new change matters more than a long-standing trait

Suppose a person has had thin nails since childhood.

That is not the same as someone who has always had strong nails but whose nails have become thin and brittle in the last six months.

In reading signs, the important question is always:

What has changed compared with before?

Sometimes this one question is worth more than dozens of scattered observations.

Which changes shouldn’t be ignored?

Some nail changes are better checked, especially when they are new, persistent or getting worse:

• A sudden, marked change in nail colour
• Nails turning blue or purple
• A new, changing dark line on a nail
• A marked change in nail shape
• The nail lifting from its bed for no obvious reason
• Excessive thickening
• Inflammation, pain or pus around the nail
• Several nails changing at the same time
• Slow healing of wounds around the nail, especially in people with diabetes

In particular, a new and changing brown or black band on a nail should not be put down only to temperament, a knock or a nutrient deficiency; it should be checked by a doctor, preferably a dermatologist.

Five simple questions for reading your nails

When you notice a change in your nails, ask these questions before drawing any conclusion:

• Has the colour changed compared with before?
• Has the shape or thickness changed?
• Is one nail affected, or several?
• Did the change come suddenly or gradually?
• Has anything else changed at the same time — skin, hair, energy, weight, breathing, digestion or other parts of the body?

These five questions can turn a simple observation into a more careful clinical view.

Don’t read the nails apart from the body

One of the biggest mistakes in reading signs is assigning a particular disease to every nail change.

For example:

“This spot means a deficiency of such-and-such vitamin.”
“This line means the liver.”
“This colour means the kidneys.”

The body doesn’t work that simply.

One sign can have several causes, and one illness can cause many different signs.

So in clinical assessment, the nails should be assessed together with the skin, hair, tongue, lips, eyes, pulse, sleep, appetite, digestion, elimination, sweating, body temperature and the person’s general condition .

This is where the difference between seeing a sign and understanding a sign becomes clear.

Conclusion: nails are silent, but not without a message

We look at our hands every day, but we rarely think that our nails record part of our body’s history.

The colour, shape, surface, thickness, strength, growth rate, half-moon, lines and changes of the nails can give us clues about the state of the skin and tissues, nutrition, the blood, circulation, oxygenation, hormones and some internal diseases.

But the most important principle is this:

Don’t diagnose a disease from a single sign.

Your nails don’t tell you, “You have this disease.”

They say:

“Something has changed here — look more closely.”

In reading signs, this “looking more closely” is where assessment begins.

When the nails are read together with the skin, tongue, hair, lips, eyes, pulse, secretions, digestion, sleep and the body’s other signs, a much fuller picture emerges.

Many people look at their body every day;
but far fewer know the body’s sign language.

Learning this language is too big a subject to cover in full in one article. Types of lines, colours, spots, changes in shape, the links between several signs, and how to tell simple changes apart from important signs are each a topic of their own.

The aim of this article was only to open a window:

Before the body speaks through pain, it sometimes speaks through signs.

And the nails are one of the places where this conversation is worth learning and reading correctly.

Further reading

Reading the signs of the nails, skin, tongue, lips, hair, eyes and the body’s other outward signs, and how to assess them together — these and other detailed topics are covered more fully, step by step, in Dr Kalan’s “Elaim & Delail” book and course set (in Turkish).

References

• Avicenna (Ibn Sina). Al-Qanun fi al-Tibb (The Canon of Medicine); sections on temperament, the humours, indications and reading the body’s signs.
• Rhazes (al-Razi), Muhammad ibn Zakariya. Al-Hawi fi al-Tibb.
• Jurjani, Sayyid Ismail. Zakhira-i Khwarazmshahi.
• Aghili Khorasani, Mohammad Hosein. Kholasat al-Hikmah.
• Wollina U, Nenoff P, Haroske G, Haenssle HA. The Diagnosis and Treatment of Nail Disorders. Deutsches Ärzteblatt International. 2016.
• Singal A, Arora R. Nail as a window of systemic diseases. Indian Dermatology Online Journal. 2015.
• Tully AS, Trayes KP, Studdiford JS. Evaluation of Nail Abnormalities. American Family Physician. 2012.
• Lipner SR, Scher RK. Evaluation of nail lines: Color and shape hold clues. Cleveland Clinic Journal of Medicine. 2016.
• Dr Kalan scientific and educational resources on sign-reading, temperament and traditional medicine.

Related articles

• Are White Spots on Your Nails a Calcium Deficiency?
• Brittle Nails: Causes and When They Matter
• Nail Ridges: Marks That Record the Body’s Past