Brittle nails, a condition clinically known as onychoschizia, are characterised by nail plates that are weak, thin, and prone to splitting or peeling in layers. This issue is very common and can affect both the fingernails and toenails, often causing discomfort or snagging on clothing. While many cases are the result of external environmental factors or the natural ageing process, brittle nails can sometimes serve as an indicator of an underlying nutritional deficiency or a systemic health condition that requires professional medical attention to resolve.
What We’ll Discuss in This Article
- The impact of environmental moisture and chemical exposure
- How the natural ageing process changes nail structure
- The role of nutritional deficiencies in nail strength
- Underlying medical conditions that cause brittle nails
- The effect of skin conditions like psoriasis and eczema
- Preventative measures and when to seek medical advice
Environmental factors and repetitive moisture exposure
The most frequent cause of brittle nails is the repetitive cycle of wetting and drying the hands and feet. When nails are immersed in water, the nail cells swell, and as they dry, they shrink, which weakens the bonds between the layers of keratin that make up the nail plate. This is why people who frequently wash their hands or those in professions involving water exposure often notice their nails become soft and split more easily at the edges.
Exposure to harsh chemicals found in household cleaning products, detergents, and even some nail polish removers can also strip the natural oils from the nail. The NHS highlights that frequent contact with water and chemicals is a primary reason why nails become weak or brittle. To protect the nails, it is often recommended to wear gloves when using cleaning agents and to use moisturising creams regularly to replenish the protective barrier of the nail and surrounding skin.
The influence of the natural ageing process
As individuals age, the body’s ability to retain moisture and produce the protective oils that keep nails flexible tends to decrease. This often results in fingernails becoming thinner and more prone to vertical ridges and splitting. Conversely, toenails may actually become thicker and more brittle with age, making them harder to trim and more likely to crack under pressure from footwear.
These changes are considered a normal part of physiological ageing and are not usually a cause for clinical concern unless they are accompanied by significant pain or changes in colour. While the structural changes cannot be entirely reversed, maintaining good foot and hand hygiene and using urea-based moisturisers can help to keep the nail plates as supple as possible. Regular trimming also prevents long nails from catching and tearing, which is more common in older, brittle nails.
Nutritional deficiencies and nail health
The health of the nail is directly linked to the body’s nutritional status, as the nail matrix requires a steady supply of vitamins and minerals to produce strong keratin. A deficiency in iron, often referred to as anaemia, is a well-known cause of brittle or spoon-shaped nails. If the body lacks sufficient iron, the nails may grow out thin and concave rather than having a healthy, slightly convex curve.
Other nutrients such as biotin, a type of B vitamin, and certain proteins are also essential for maintaining nail integrity. NICE clinical guidelines suggest that a balanced diet is fundamental for healthy skin and nails, and deficiencies can often manifest as changes in nail texture. If you suspect a nutritional issue, a healthcare professional can perform a blood test to check your levels and determine if dietary changes or supplements are necessary.
Underlying systemic medical conditions
Brittle nails can sometimes be a secondary symptom of a systemic health issue, particularly those affecting the thyroid gland. Both an overactive thyroid (hyperthyroidism) and an underactive thyroid (hypothyroidism) can alter the metabolic rate of nail production, leading to nails that are dry, slow-growing, and prone to breaking. In these cases, the nail problems are usually accompanied by other symptoms such as changes in energy levels, weight, or skin texture.
Circulatory problems, such as Raynaud’s phenomenon, can also affect nail strength. This condition causes the blood vessels in the fingers and toes to narrow excessively in response to cold, reducing the supply of oxygen and nutrients to the nail matrix. Over time, this repeated lack of blood flow can cause the nails to become permanently brittle and thin. Managing the underlying condition is the most effective way to restore the health of the nails in these scenarios.
Impact of skin conditions and fungal infections
Common skin conditions such as psoriasis and eczema can directly affect the area where the nail is formed. Nail psoriasis often causes pits, ridges, and a crumbling texture that makes the nail extremely brittle. The inflammation associated with these conditions can disrupt the normal growth cycle, leading to nails that are structurally unsound and split easily even with minimal trauma.
Fungal nail infections, or onychomycosis, are another significant cause of brittle toenails. The fungi feed on the keratin in the nail, causing it to become thickened, discoloured, and very brittle. As the infection progresses, the nail may begin to crumble at the edges or lift away from the nail bed. Treating the fungal infection with appropriate topical or oral medications is necessary to stop the destruction of the nail plate and allow a healthy nail to grow back.
When to seek professional medical advice
While brittle nails are often a minor issue, you should seek medical advice if the changes are sudden, severe, or affect all of your nails simultaneously. If you notice horizontal ridges (Beau’s lines), significant discolouration, or if the skin around the nail becomes inflamed and painful, a clinical assessment is required. These signs can indicate a more serious systemic illness or a significant infection that needs targeted treatment.
A healthcare professional can examine the nails and may take a small clipping for lab analysis if a fungal infection is suspected. They will also look at your overall health history to see if the nail changes align with any other symptoms, you may be experiencing. Early diagnosis of any underlying condition not only helps to improve the appearance of your nails but also ensures that your broader health is being properly managed.
Conclusion
Brittle or splitting nails are often caused by environmental factors like frequent water exposure, but they can also be linked to ageing, nutritional deficiencies, or thyroid issues. Protecting your hands with gloves and maintaining a balanced diet are key steps in preserving nail strength. If you notice persistent or painful changes in your nails, it is important to consult a clinician for a full evaluation. If you experience severe, sudden, or worsening symptoms, call 999 immediately.
Can wearing nail polish make my nails brittle?
The polish itself is usually fine, but the frequent use of acetone-based removers can strip the nail of its natural moisture, leading to dryness and splitting.
Is it true that gelatine supplements help strengthen nails?
There is very little clinical evidence to support the idea that eating gelatine significantly improves nail strength compared to a balanced protein intake.
Why do my fingernails split but my toenails are fine?
This is often because the fingernails are exposed to more water and chemicals through daily tasks like washing dishes or cleaning compared to protected toenails.
How long does it take for a nail to grow out healthy again?
Fingernails take about six months to grow out completely, while toenails can take up to a year, so improvements in nail health will take time to become visible.
Can a lack of calcium cause brittle nails?
While calcium is important for bones, nail strength is more closely related to protein, iron, and biotin levels rather than calcium alone.
Does biting my nails make them more prone to splitting?
Yes, biting creates jagged edges and introduces moisture and bacteria, which weakens the nail structure and makes it more likely to peel or split.
Should I use a nail hardener to fix brittle nails?
Nail hardeners can provide temporary support but using them too frequently can actually make the nail too rigid and more likely to snap under pressure.
Authority Snapshot (E-E-A-T)
This article is designed to provide clear and factual information regarding skin health for the general public. The content is written by the Medical Content Team and has been reviewed by Dr. Stefan Petrov. He is a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). He has hands-on experience in general medicine, surgery, anaesthesia, ophthalmology, and emergency care. Dr. Petrov has worked in both hospital wards and intensive care units, performing diagnostic and therapeutic procedures, and has contributed to medical education by creating patient-focused health content and teaching clinical skills to junior doctors.
