Causes of Dry, Brittle Hair (And How To Fix It)

Brittle hair is dry, rough hair that is prone to breakage. Brittle hair symptoms include hair strands that look frizzy, dull, or have a lot of split ends.

Some people may have brittle hair at the ends of their hair, caused by chemical processing, heat damage, or lack of proper care. Others may have brittle hair right from the root, which is typically caused by a hair shaft disorder. Brittle hair can also be caused by infection, systemic illnesses, poor diet, or it can simply be part of the aging process. (1,2)

What Does Brittle Hair Look Like?

Brittle hair typically looks dry, dull, frizzy, and rough in texture. Split ends can often be seen, as well as uneven hair growth due to broken hair shafts. Brittle hair can be prone to tangling and is difficult to manage. It usually appears spongy when wet and frizzy when dry. It may also appear kinky, coarse, or seem stiff. (1,3)

When brittle hair is caused by chemical processing, heat damage, or problems with how an individual cares for their care, it’s often seen at the ends of the hair rather than at their roots. In contrast, when brittle hair is caused by a hair shaft disorder, nutritional deficiency, or an illness, it can be brittle right from the root. Regardless of the cause, if brittle hair is left untreated, it can lead to hair loss over time. (1,3)

What Causes Brittle Hair?

Brittle hair can be caused by lifestyle factors, such as chemical damage, heat damage, certain hairstyles, and not taking care of your hair well. It can also be caused by hair shaft disorders, infections, systemic illnesses, and congenital abnormalities. Nutrient deficiencies can lead to brittle hair because the body isn’t getting the nutrients it needs to stay healthy. (1)

What Are the Medical Causes of Brittle Hair?

There are many medical conditions that can cause brittle hair, including hair shaft disorders, scalp infections, and systemic illnesses like COVID. Thankfully, these causes can often be managed, and hair health can be improved. (1)

Inherited Hair Shaft Disorders

There are multiple hair shaft disorders that are genetic. This means that you can inherit them from your parents.

Trichothiodystrophy (TTD) refers to a group of genetic disorders which cause short, dry, brittle hair that is low in sulfur content. Our hair is made from keratin, which is high in sulfur content. Sulfur gives hair strength and elasticity. When it’s lacking, this can lead to brittle hair. (4)

TTD is a rare disorder, inherited through recessive genes. Aside from causing brittle hair, the hair can also have a light and dark banding pattern which is often known as a ‘tiger tail’ pattern. TTD hair shafts will typically show multiple breaks and fraying. (4)

There are multiple other symptoms of TTD which affect the rest of the body, including neurological symptoms, issues with growth, skin conditions, vision problems, and sensitivity to ultraviolet radiation (UV). Treatment of TTD is limited, with a multidisciplinary approach required. (4)

Menkes disease (MD), also known as kinky hair disease, trichopoliodystrophy, or steely hair disease, is another rare recessive disorder. It’s a progressive neurodegenerative disorder that causes a range of symptoms including dry, thin, brittle hair that is light in pigmentation. Hair often breaks, leading to hair loss over time. Hair shaft abnormalities caused by Menkes disease often present as pili torti. (5)

Pili torti is a hair shaft disorder that causes short hair and breaks easily. The hair appears coarse, sparse, and dry. The condition causes hair strands to be flattened and twisted to 180 degrees at regular intervals along the shaft. Pili torti can occur on its own or be caused by other conditions, such as Menkes disease. There’s no treatment for the condition, but it does tend to improve after puberty. (6)

Monilethrix is a rare genetic disorder causing sparse, dry, and brittle hair strands. The hair is very prone to breakage and typically doesn’t grow more than a couple of inches in length. The condition can cause raised papules which indicate that the hair follicles are blocked by a build-up of keratin. There’s no specific treatment for the disorder, but it can often resolve as the child gets older. (7)

Wooly hair is a rare congenital structural anomaly affecting the hair. It causes extremely curly hair with a texture similar to sheep’s wool. Typically the hair is short, brittle, and dry. This type of hair is extremely curly – but instead of the curls being separate, they merge together to create a wooly texture. There is no treatment for the condition. (8)

Uncombable hair syndrome is a rare hair shaft disorder causing silvery-blond or straw-colored hair that stands out from the scalp. The hair is usually messy, difficult to comb, and won’t lie flat, even when styled. There’s no treatment for this condition, but it often resolves later in childhood. (9)

Scalp Infections

In some cases, infections of the scalp can damage the hair shaft, leading to brittle hair and breakage. Piedra is a fungal infection that causes nodules on the hair shafts. There are two types: black piedra and white piedra. Black piedra causes larger, harder nodules than white piedra. Both can affect the scalp, as well as other areas of the body where hair grows. Treatment can involve shaving the head or antifungal treatments. (1,10)

Systemic Illnesses

Systemic illnesses affect the whole body, so it’s no surprise that they can affect the health of your hair. Some systemic illnesses can cause brittle hair, including hypothyroidism. Hypothyroidism is an underactive thyroid, which means the thyroid gland isn’t producing enough of the thyroid hormone. Thyroid hormones play an important part in the growth and maintenance of healthy hair. (11)

Hypothyroidism can cause a range of symptoms, including rough and brittle hair. Patients with hypothyroidism can also experience alopecia. Treatment involves medication to increase levels of the thyroid hormone which can reduce symptoms. (11)

During the COVID-19 pandemic, a large number of people reported changes in hair growth and texture. A prospective cross-sectional study found that out of 1,893 people, 50 percent reported having brittle, dry, or dull hair. In the same study, 68 percent of people reported that they had experienced hair loss. Research suggests that this may be due to changes in lifestyle habits, such as frequent hair washing during the pandemic, as well as hair loss potentially stemming from the systemic infection. (12)

What Deficiency Causes Brittle Hair?

What we eat is the fuel we give our body to function. When our bodies don’t get the right nutrients, it can cause multiple health problems. A number of nutritional deficiencies have been linked to brittle hair, as well as hair loss. (13)

Zinc is a mineral that is essential for our bodies to function properly. A zinc deficiency can cause a range of symptoms, including brittle hair and telogen effluvium. Telogen effluvium is also known as stress-related hair loss. It occurs after a mentally or physically stressful event, or when the body is under stress because it isn’t getting the nutrients it needs. (13)

Selenium is a trace element known as an antioxidant, which does lots of important jobs, including helping to protect the human body from chronic diseases. It also plays a pivotal role in thyroid function. A selenium deficiency can lead to brittle hair among other symptoms. If left untreated for a long time, it can cause thyroid disease, which in turn, can cause brittle hair and hair loss. (14)

Vitamin C is a crucial part of our diet. When we don’t have enough, it can cause a condition called scurvy, which is associated with vitamin C deficiency. This can lead to serious health issues, including brittle hair and hair loss. (15)

Vitamin B12 is a water-soluble vitamin that helps with lots of important bodily processes, including metabolism, making red blood cells and DNA, and maintaining healthy nerve function. Vitamin B12 deficiency can cause brittle hair as well as premature depigmentation of hair, causing early hair greying. (16)

Poor Treatment Can Cause Hair Shaft Anomalies

How we look after our hair can have a big impact on its health. Poor treatment, for example, using heat frequently, or excessive chemical processing through bleaching and dyeing can lead to brittle hair. (3)

Bubble hair is a hair shaft deformity caused by using heat on the hair. It causes bubble-like areas in the hair shaft that can only be seen under a microscope. To the naked eye, hair will appear dry, wiry, and brittle. It can be very fragile and break off, leaving uneven hair or causing areas of patchy hair loss. 

There are a number of other hair shaft conditions that can be caused by poor treatment of the hair, including trichorrhexis nodosa and trichoptilosis. There’s no way to fix hair shafts once they’re broken. You’ll need to wait for healthy hair to grow in from the root, which takes time. (3)

How Do You Fix Brittle Hair?

Many people wonder: can brittle hair be restored? But whether or not you can fix brittle hair depends on the cause. When it comes to inherited hair shaft disorders such as uncombable hair syndrome, wooly hair, monilethrix, and pili torti, brittle hair can’t be fixed. However, symptoms often resolve as the child gets older. (6-9)

Treatment of trichothiodystrophy takes a multi-disciplinary approach to manage the symptoms and help the patient cope. (4) Sadly, Menkes disease treatment focuses on making the patient comfortable. Life expectancy for children with this condition is short, at just 3 years old. (5)

Treatment of scalp infections will vary depending on the type of infection. But typically, once the cause is treated, the hair’s health will improve. Fungal infections like piedra are usually treated with either topical or oral antifungal agents. The best way to get rid of the infection is to shave the head, treat the issue, and allow healthy hair to grow back. Obviously, not all patients feel comfortable with this option. (10)

With systemic illnesses like COVID-19 and hypothyroidism, once the illness is treated and resolved, the hair’s health will typically be restored. However, this depends on the extent of the changes to the hair and how well the patient recovers. (11,12)

Similarly, once nutritional deficiencies are corrected either through diet, supplements, or treating underlying causes, brittle hair will usually be resolved. If hair has been lost, it will regrow over time. (13)

When brittle hair is caused by poor treatment, in some cases it may be reversed. Unfortunately, if the hair shaft is damaged, as occurs with bubble hair, this can’t be reversed. However, patients can work on changing the habits that caused the condition in order to prevent further damage. (3)

Brittle hair can cause the hair to appear very dry. Brittle hair treatment often revolves around trying to improve the appearance of the hair to boost confidence. This might involve using moisturizing products or wearing hair in certain styles. Some people might also wear hair pieces or wigs to help them achieve their preferred look. It’s important to help people with brittle hair rebuild their confidence, especially if the condition is not reversible. 

Why Does Dry, Brittle Hair Occur and Can You Treat It?

Brittle hair can occur due to inherited hair shaft disorders, although these are quite rare. Common causes include scalp infections, such as fungal infections, and systemic illnesses. Nutritional deficiencies can also play a big part in hair health and can lead to dry, brittle hair. Poor treatment can also lead to brittle hair by causing damage to the hair shaft.

In many cases, brittle hair can be resolved once the underlying cause is dealt with. However, with some conditions where the hair shaft is damaged, it can’t be reversed. Instead, the focus should be on preventing further damage and focusing on new, healthy hair growth.