What Are Nails Made of? Here Is What the Evidence Says

Nails are made mainly of keratin, a tough protective protein also found in hair and the outer layer of skin. Most nail changes are harmless, but some patterns can point to infection, injury, skin disease, or broader health problems and may need medical review.

What nails are made of

When people ask, “what are nails made of,” the short answer is keratin. Keratin is a strong, fibrous protein that also helps form hair and the outer protective layer of skin. In nails, keratin is packed tightly into layers, which is why nails feel firm and can protect the tips of the fingers and toes.

The visible part of the nail, called the nail plate, is made of hardened, dead keratinized cells. These cells were once living cells in the nail matrix, the growth area hidden under the skin near the base of the nail. As new cells are made in the matrix, older cells are pushed forward, flatten, harden, and form the nail plate.

Nails also contain small amounts of water and trace minerals, but they are not “made of calcium” in the way many people assume. Calcium is important for overall body function, yet the strength and structure of nails come mainly from how keratin is produced and arranged. This is why nail health depends not only on nutrition, but also on skin health, circulation, hormones, and protection from injury and chemicals.

How the nail is built

Understanding nail structure helps explain why nails can change in different ways. The main parts include the nail matrix, nail plate, nail bed, cuticle, and surrounding skin folds. The matrix is the engine of nail growth. The nail plate is the hard part that is seen. The nail bed is the tissue beneath the plate, which supports it and contributes to its pink color.

The cuticle forms a small seal between the skin and the growing nail. This seal helps keep out water, irritants, and germs. Around the edges, the nail folds protect the sides and base of the nail. When these areas become damaged, infections and inflammation can develop more easily.

The pale half-moon sometimes seen at the nail base is called the lunula. It is a visible part of the matrix in some people, but not all. Nail growth is usually slow and steady, and fingernails generally grow faster than toenails. Because nails grow gradually, changes from illness, injury, or nutritional problems may not appear immediately.

• Nail matrix: makes new nail cells
• Nail plate: hard keratin layers that form the visible nail
• Nail bed: skin under the nail plate
• Cuticle: protective seal at the nail base
• Nail folds: skin around the nail edges

Why nails look and feel the way they do

The strength, smoothness, thickness, and flexibility of a nail depend on the quality of keratin formation and the condition of the tissues around it. Healthy nails are usually relatively smooth, evenly colored, and firmly attached to the nail bed. They may vary naturally from person to person in thickness and shape.

Everyday factors can affect the nail surface. Repeated hand washing, cleaning products, nail cosmetics, and minor trauma can dry out nails or make them brittle. Habits such as picking, biting, or aggressive manicure techniques can also damage the cuticle and matrix, leading to ridges, peeling, or irregular growth.

Some changes in nails come from skin conditions rather than the nail itself. For example, eczema, chronic irritation, and psoriasis can alter nail texture, create pitting, or cause the nail to lift away from the bed. Fungal infection may thicken, discolor, or crumble the nail over time. A doctor may evaluate persistent changes to rule out nail fungus and other causes.

Common nail changes and what they may mean

Many nail changes are harmless and relate to age, dryness, or repeated minor injury. Longitudinal ridges, for example, often become more noticeable over time and are not always a sign of disease. Temporary white spots are commonly caused by small injuries to the nail matrix rather than a lack of calcium.

Other changes deserve a closer look. Brittle, splitting nails can be linked to frequent water exposure, detergents, or inflammatory skin conditions. Thickened or yellow nails may occur with fungal infection, aging, or pressure from shoes. Nails that lift from the bed, called onycholysis, can happen after trauma, with skin disorders, or with thyroid-related conditions.

Color can also matter. Pale nails, dark streaks, greenish discoloration, or a blue or gray tone may point to different issues and should be assessed in context. Clubbing, spoon-shaped nails, painful swelling around the nail, or sudden marked changes in one nail are more specific findings that may prompt broader medical evaluation. The goal is not to assume the worst, but to recognize patterns that are worth discussing with a qualified doctor.

What can affect nail growth and health

Nail growth depends on healthy matrix function, blood supply, and overall skin health. Nutrition plays a role, especially if a person has a significant deficiency or poor absorption, but nails do not usually reflect one single vitamin or mineral in a simple way. General health conditions, hormonal changes, circulation problems, and inflammatory diseases can all influence the way nails grow.

Infections are another common factor. Fungal infections are especially frequent in toenails, while bacterial infections may affect skin around the nail after trauma, picking, or trimming too deeply. Repeated friction, sports injuries, tight shoes, and occupational exposure to moisture or chemicals can also lead to splitting, thickening, discoloration, or deformity.

Because nails can reflect both local and systemic issues, evaluation sometimes involves more than the nail itself. Dermatologists may assess the surrounding skin, scalp, joints, or medical history to identify conditions such as dermatitis, fungal infection, autoimmune disease, or circulation problems. In selected cases, tests related to dermatology evaluation or general health check-up may help clarify the cause.

How doctors assess nail problems

Most nail concerns are evaluated with a careful history and physical examination. A doctor may ask when the change began, whether one nail or many nails are involved, whether there has been trauma, and whether there are symptoms such as pain, itching, drainage, or swelling. They may also ask about medications, occupational exposures, cosmetic products, skin conditions, and family history.

The nails are then examined closely for color, shape, thickness, attachment to the nail bed, surrounding skin changes, and patterns that suggest inflammation or infection. Looking at both fingernails and toenails can be helpful, as some conditions affect them differently. The doctor may also inspect the skin and hair because nail findings can accompany broader skin disorders.

If needed, additional tests may be used. These may include taking nail clippings or scrapings to look for fungus, swabbing drainage if infection is suspected, or doing blood tests when a systemic issue is considered. In selected cases, a biopsy of the nail unit may be recommended to clarify a diagnosis, especially if there is a persistent dark band, an unexplained growth, or a change that does not improve with standard treatment.

Treatment and nail care

Treatment depends on the cause. Dry, brittle nails may improve with gentler nail care, reduced exposure to harsh products, and regular moisturizing of the nails and cuticles. If a person uses nail cosmetics, giving the nails periodic breaks and avoiding aggressive cuticle removal may help protect the matrix and surrounding skin.

When infection is the cause, treatment may involve topical or oral medicines chosen by a doctor. Inflammatory conditions such as eczema or psoriasis may be managed with treatments directed at the skin and nail unit. If trauma or pressure is contributing, changes in footwear, trimming habits, or hand protection can be important parts of care. For persistent or complex cases, referral for specialist dermatology care may be appropriate.

Not every nail abnormality can be corrected quickly, because nails grow slowly. Improvement may take weeks to months as healthier nail grows in. Near the end of care planning, some people may also seek evaluation at centers such as Acibadem International, where multidisciplinary specialists in JCI-accredited hospitals assess and treat nail, skin, and related health concerns for international patients.

When to seek medical care

Most nail changes are not emergencies, and many are harmless. Still, medical attention is sensible if a nail problem is persistent, painful, spreading, or affecting daily activities. Prompt review is especially important when there is redness, warmth, swelling, pus, fever, or significant tenderness around the nail, as these features can suggest infection.

It is also wise to seek care for a new dark streak or spot in the nail, sudden separation of the nail from the nail bed, bleeding without a clear injury, a growth under or around the nail, or major change affecting just one nail. People with diabetes, poor circulation, immune suppression, or ongoing foot problems should be particularly cautious with toenail changes.

Until a doctor assesses the problem, it is best to avoid picking, digging under the nail, or using strong over-the-counter products on damaged skin. Keeping the area clean, dry, and protected can help. If symptoms are worsening or there is concern about an underlying condition, a clinician may coordinate further care, including dermatology assessment or related specialty review.

Frequently asked questions

Are nails made of calcium?

No. Nails are made mainly of keratin, which is a structural protein. Calcium supports many body functions, but it is not the main substance that forms the nail plate.

Are nails living tissue?

The visible nail plate is made of dead, hardened cells. However, the nail grows from living tissue in the nail matrix under the skin at the base of the nail.

Why do nails get brittle or peel?

Brittle or peeling nails are often linked to dryness, repeated water exposure, detergents, nail cosmetics, or minor trauma. Sometimes they are associated with skin conditions or other medical issues, so persistent changes should be evaluated.

Do white spots on nails mean a vitamin deficiency?

Usually not. Small white spots are commonly caused by minor injury to the nail matrix. If nail changes are widespread, persistent, or accompanied by other symptoms, a doctor can assess whether further evaluation is needed.

How can a doctor tell if a nail problem is fungal?

A doctor looks at the pattern of nail changes and may take a sample of nail material for testing. This can help confirm fungus and distinguish it from conditions like psoriasis, trauma, or eczema.

When is a dark line in the nail concerning?

A new or changing dark band, especially if it involves one nail or extends onto the surrounding skin, should be assessed by a doctor. Many causes are benign, but this pattern deserves prompt professional evaluation.

References

• American Academy of Dermatology
• National Health Service
• Merck Manual Consumer Version
• Mayo Clinic
• DermNet

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.