A close-up photo capturing a hand holding a strand of hair and a broken nail, symbolizing the connection between hair loss, brittle nails, and potential health issues.

Hair Loss And Brittle Nails: What They Could Mean For Your Health

If you’ve noticed more hairs than usual on your hairbrush or your nails seem more brittle lately, you may be wondering what’s going on. Hair loss and brittle nails can indicate an underlying health issue.

If you’re short on time, here’s a quick answer to your question: Hair loss and brittle nails are often a sign of nutritional deficiencies, thyroid disorders, or other systemic imbalances in the body. Identifying and addressing the root cause is key to resolving these outward symptoms.

In this comprehensive guide, we’ll explore the most common reasons for hair loss and brittle nails. We’ll look at which nutritional deficiencies to watch out for, what thyroid issues could be at play, and when it’s time to see your doctor for bloodwork and further evaluation.

Read on to learn what your hair and nails may be trying to tell you about your health.

Common Nutritional Deficiencies That Can Cause Hair Loss and Brittle Nails

Iron Deficiency or Anemia

Iron deficiency is one of the most common causes of hair loss. When you don’t have enough iron in your body, it reduces the supply of oxygen and nutrients to your hair follicles, which can make them shrink and stop growing hair.

Anemia, characterized by low iron levels, is also associated with brittle nails that crack or split easily.

Getting adequate iron from your diet or supplements helps stimulate new hair growth and promotes strong, healthy nails. Great iron-rich food sources include red meat, beans, lentils, spinach, and fortified whole grain cereals.

If your doctor diagnoses an iron deficiency, they will likely recommend taking an iron supplement to get your levels back to normal.

Zinc Deficiency

Zinc is an essential mineral that plays many critical roles in hair tissue growth and maintenance. Some studies estimate that over 30% of people with hair loss are deficient in zinc.

Without enough zinc in your diet, your hair follicles and nail beds don’t get the nutrients they need. This can lead to increased hair shedding or slow regrowth, as well as white spots and increased brittleness in fingernails and toenails.

Foods high in zinc include oysters, red meat, poultry, beans, nuts, and dairy products. Taking a zinc supplement may also help prevent hair and nail problems if you are deficient.

Biotin (Vitamin B7) Deficiency

Biotin is an important B vitamin that supports many aspects of health, including your hair, skin, and nails. In fact, biotin deficiency is one of the most rapidly growing nutritional problems linked to hair loss.

Getting adequate biotin can help strengthen brittle nails and improve hair elasticity, reducing breakage. Foods rich in biotin include organ meats, eggs, fish, meat, seeds, nuts, and sweet potatoes. Many people take a daily biotin supplement for optimal hair, skin, and nail health.

Vitamin D Deficiency

Emerging research shows a strong connection between low vitamin D levels and hair loss. One study found that women with hair loss had significantly lower vitamin D levels than those with healthy hair.

Vitamin D helps regulate cell growth and function in the hair follicles. A deficiency can disrupt the hair growth cycle, leading to excessive shedding or slow regrowth. Vitamin D also plays a role in the formation of strong nails.

Getting 10-15 minutes of midday sunlight provides your daily dose of vitamin D. You can also find it in fatty fish, egg yolks, and vitamin D-fortified foods like milk. Many people take a vitamin D supplement, especially during the winter.

Thyroid Issues That May Lead to Hair and Nail Changes


Hypothyroidism, also known as underactive thyroid, is a common condition where the thyroid gland does not produce enough thyroid hormones. This can lead to symptoms like fatigue, weight gain, feeling cold, and even hair loss and brittle nails.

Here’s a deeper look at how hypothyroidism affects your hair and nails:

When the thyroid is underactive, it slows your metabolism. This reduces the rate that old hair cells are shed and replaced by new ones. As a result, hypothyroid patients often notice thinning hair, dry hair, and excessive hair loss. The hair that remains may become brittle and dull.

Similarly, hypothyroidism slows the nail growth rate and affects keratin production. Many patients with hypothyroidism develop brittle, fragile nails that chip and break easily. There may also be longitudinal ridges or grooves running down the nail.

Studies show that 50-80% of hypothyroid patients experience hair loss or brittle nails. For example, a 2019 study found that 63% of hypothyroid patients had nail issues while 56% had scalp hair problems.

The good news is that these symptoms often improve when hypothyroidism is treated with thyroid hormone replacement medication. Thyroid hormones stimulate hair regrowth and strengthen the nails. So proper treatment can help restore your hair and nails to a healthy state.


On the flip side, hyperthyroidism is when the thyroid is overactive and produces too much thyroid hormone. Symptoms include unexplained weight loss, rapid heartbeat, tremors, and even hair and nail changes in some cases.

One study found that around 28% of hyperthyroid patients experienced hair loss. The excessive thyroid hormones likely push large numbers of hair follicles into the resting phase prematurely. This results in telogen effluvium, a form of temporary but excessive shedding.

Interestingly, hyperthyroidism seems to affect nails differently than hypothyroidism. One study on thyroid disorders found that patients with overactive thyroid were more prone to develop clubbed nails. This is characterized by enlargement of the fingertips and increased nail curvature.

Once hyperthyroidism is treated and thyroid hormone levels normalize, the hair and nails abnormalities usually resolve. So the key is getting an accurate diagnosis and proper treatment as soon as possible.

Other Potential Medical Causes

Skin Disorders Like Psoriasis

Certain skin conditions like psoriasis can also lead to brittle nails and hair loss. Psoriasis causes red, scaly patches on the skin and affects around 2-3% of people. The exact cause is unknown but it’s thought to be an autoimmune disorder.

A study in 2016 found that around 39% of people with psoriasis also experienced nail changes like pitting, crumbling and detachment. Hair loss or thinning hair, also called alopecia, affects around 40% of those with psoriasis.

The flakiness and scaling of the scalp associated with psoriasis is thought to damage hair follicles over time, resulting in thinning hair or patchy hair loss.

Systemic Illnesses Such as Lupus

Systemic autoimmune diseases like lupus can also sometimes cause changes in fingernails and hair. According to the Lupus Foundation of America, around 45% of people with lupus experience hair loss or thinning hair, which is medically termed alopecia.

Lupus causes the immune system to attack the body’s own healthy cells and tissues, resulting in widespread inflammation that can damage hair follicles. Specific medications used to treat lupus like corticosteroids may also contribute to hair loss as a side effect.

Regarding nails, a study in the journal Arthritis Care and Research found that around 25% of lupus patients had nailfold changes like thickening, colour changes, and abnormal shapes.


Certain medications can also sometimes lead to brittle nails and hair loss as side effects. For example, drugs used in chemotherapy to treat cancer often damage quickly dividing cells like those in hair follicles, resulting in temporary hair loss.

Acne medications like isotretinoin are also associated with hair thinning. Some supplements like high-dose vitamin A or vitamin B6 may lead to hair and nail issues when taken excessively. The antifungal medication griseofulvin has been associated with hair and nail fragility.

Even common OTC drugs like antacids may cause brittle nails in some people. It’s important to be aware of any new medications and report changes in nails or hair to a doctor to rule out drug side effects.

When to See a Doctor

Sudden Hair Loss

If you notice a substantial amount of hair falling out all at once, it’s important to see your doctor. Sudden hair loss can be caused by physical or emotional shock, certain medications, or an underlying medical condition. Some possible causes include:

  • High fever, severe infection, major surgery – This type of sudden hair loss usually causes telogen effluvium, where a large number of follicles enter the telogen (resting) phase at the same time. Hair typically grows back within 6 months.
  • Very stressful event – Emotional trauma can cause hair follicles to go into shock, leading to sudden hair loss. Examples include death of a loved one, divorce, job loss. Hair usually regrows after the stress is resolved.
  • Hormonal changes – Significant hormonal changes can disrupt the hair growth cycle and cause sudden hair loss. This includes thyroid disorders, childbirth, discontinuing birth control pills.
  • Nutritional deficiency – Lack of protein, iron, zinc or other essential nutrients can hamper hair growth and lead to sudden shedding.
  • Medications – Drugs that can cause sudden hair loss include retinoids, beta blockers, anticoagulants, NSAIDs, antidepressants.

Seeing a doctor can help determine the underlying cause of sudden hair loss. Blood tests may identify nutritional deficiencies, hormone imbalances or other medical conditions. Your doctor may adjust medications or treat any underlying issues to stop further hair shedding.

Hair Loss Along with Other Symptoms

It’s crucial to see a doctor if hair loss occurs along with other symptoms, as this may indicate an underlying medical condition that requires treatment. Be sure to get evaluated if you have hair loss accompanied by:

  • Fatigue, weight loss or loss of appetite – Could signal thyroid problems, anemia or autoimmune disorders.
  • Facial hair growth in women – Suggests hormonal imbalance like polycystic ovary syndrome.
  • Sudden hair loss in patches – Indicates alopecia areata, an autoimmune disorder.
  • Scalp redness, burning or itching – May point to skin infection, ringworm, psoriasis or seborrheic dermatitis.
  • Nail changes – Brittle, grooved or discolored nails can be a sign of thyroid disease, alopecia areata or fungal infection.

Diagnostic tests like blood work, scalp biopsy or imaging studies may be needed to determine the exact cause of hair loss. Early treatment improves outcomes for conditions like thyroid imbalance, scalp infections and alopecia areata.

Ongoing Brittle Nails

Brittle nails that crack or split easily can be embarrassing and painful. See your doctor if you have persistent brittle nails for more than 2 months. Possible causes include:

  • Nutrient deficiencies – Iron, calcium, zinc, biotin deficiency can weaken nails. Blood tests can check for deficiencies.
  • Thyroid disorders – Both hyperthyroidism and hypothyroidism cause nail brittleness.
  • Fungal infections – Infections make nails crumbly and discolored. Scrapings can be examined under a microscope.
  • Psoriasis – Pitting, separating from the nail bed and discoloration may indicate psoriasis.
  • Excessive manicures – Frequent wetting, drying, filing, false nails can damage nail matrix.

Treatments will depend on the specific cause but may include oral medications, topical ointments, reducing manicures and applying moisturizers. If brittle nails remain uncontrolled, your doctor may refer you to a dermatologist for specialized care.

Tips for Strengthening Hair and Nails

Eat a Nutrient-Rich Diet

Getting adequate nutrients from your diet is crucial for healthy hair and nails. Focus on eating foods rich in vitamins A, C, D, E, iron, zinc, biotin, omega-3s, protein and antioxidants. Great options include salmon, nuts, seeds, eggs, citrus fruits, spinach, broccoli, sweet potatoes and avocados.

Eating a balanced diet with plenty of whole foods can make a big difference.

Take Supplements If Needed

While diet should always come first, supplements can fill any nutritional gaps. Speak with your doctor to see if you could benefit from supplements, especially vitamin D, iron, zinc, biotin or omega-3s.

Research shows supplements like these may boost hair and nail growth when dietary intake is inadequate. Just don’t rely too heavily on pills at the expense of real food.

Use Topical Treatments

Certain oils, creams and other topical products may improve hair and nail health. For example, castor oil, coconut oil and argan oil contain fatty acids that may strengthen hair and repair split ends when applied directly.

Some nail hardeners and cuticle creams contain keratin, biotin and other compounds to protect nails. However, benefits are modest for most topical treatments.

Manage Stress

High stress levels raise cortisol, which can negatively impact hair and nails. Try to minimize daily stress through yoga, meditation, deep breathing, journaling or other relaxation techniques. Getting enough high-quality sleep is also essential.

Furthermore, sudden weight loss, trauma or illness can shock the body and disrupt hair growth cycles, leading to excess shedding.


In summary, hair loss and brittle nails are often signs that something is amiss internally. Nutritional deficiencies, thyroid problems, and other medical conditions can underlie changes in your hair and nails.

Identifying and addressing the root cause is key to revitalizing your hair and nails from the inside out. Don’t ignore these outward cues from your body – with proper care and treatment, you can restore strength and luster to your hair and nails.

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