Understanding What Are the Symptoms of Biotin Deficiency

October 1, 2025 •

4 min read

According to the National Institutes of Health, severe biotin deficiency in healthy individuals eating a normal diet has never been reported. Nevertheless, it is important to be able to identify what are the symptoms of biotin deficiency, as it can occur due to certain medical conditions, medications, or specific dietary habits.

Quick Summary

This guide outlines the signs of biotin deficiency, such as hair thinning, skin rashes, and brittle nails. It also covers more severe neurological symptoms, common causes, and risk factors associated with this rare condition.

Key Points

Hair Loss: Biotin deficiency can cause thinning hair or total hair loss (alopecia), due to its role in producing the protein keratin.
Skin Rashes: A scaly, red rash, particularly around the eyes, nose, and mouth, is a characteristic sign of biotin deficiency.
Brittle Nails: Biotin is essential for healthy nails; a lack can result in brittle, thin, or splitting fingernails.
Neurological Symptoms: Severe deficiency may lead to neurological issues, including depression, lethargy, hallucinations, and seizures.
Risk Factors: Risk factors include certain inherited disorders, long-term use of anticonvulsant or antibiotic medications, excessive consumption of raw egg whites, and pregnancy.
Fatigue and Weakness: Since biotin is involved in energy metabolism, a deficiency can cause chronic fatigue, muscle pain, and overall weakness.

Common Symptoms of Biotin Deficiency

Biotin, also known as vitamin B7, plays a vital role in the metabolism of fats, carbohydrates, and amino acids. Though a severe dietary deficiency is rare, knowing the signs can help in early detection and treatment. Symptoms can range from mild cosmetic issues to more severe neurological problems in advanced cases.

Hair and Nail Changes

Some of the most recognizable indicators of low biotin levels affect the hair and nails due to its role in keratin production.

Hair loss: Also known as alopecia, this can appear as thinning hair or significant hair loss all over the body.
Brittle hair: Hair strands may become weak and fragile, leading to increased breakage.
Brittle nails: Nails may become thin, fragile, or prone to splitting and breaking.

Skin Manifestations

Biotin is essential for maintaining healthy skin. A deficiency can cause several dermatological problems.

Scaly, red rash: Often appearing around body openings such as the eyes, nose, and mouth. This periorificial rash can be scaly and erythematous.
Dry skin: The skin may feel noticeably dry and itchy.
Dermatitis: Biotin deficiency can lead to seborrheic dermatitis.
Fungal infections: Skin lesions can create an environment favorable for fungal infections, such as candidiasis, which may be resistant to standard treatment until biotin levels are corrected.

Neurological and Systemic Effects

In more severe or untreated cases, a lack of biotin can impact the nervous system, leading to systemic symptoms.

Depression and lethargy: Mood changes, including depression, and profound fatigue are common.
Hallucinations: Visual or auditory hallucinations can occur in severe cases.
Paresthesias: This symptom is often described as a burning or tingling sensation in the hands and feet.
Seizures: In the most severe cases, particularly with inherited biotinidase deficiency, seizures can develop.
Muscle pain (myalgia): Generalized muscle pain is another possible symptom.

Causes of Biotin Deficiency

While nutritional deficiency is rare, several factors can increase the risk of developing low biotin levels.

Genetic disorders: Inherited metabolic disorders like biotinidase deficiency (BTD) or holocarboxylase synthetase deficiency impair the body's ability to utilize or recycle biotin.
Excessive consumption of raw egg whites: Raw egg whites contain a protein called avidin, which binds to biotin and prevents its absorption. Cooking eggs denatures avidin, eliminating this risk.
Chronic alcoholism: Long-term alcohol consumption can inhibit biotin absorption in the gut.
Pregnancy: Many pregnant women develop marginal biotin deficiency due to increased metabolic demands.
Medications: Prolonged use of certain drugs, such as anticonvulsants and antibiotics, can interfere with biotin metabolism and absorption.
Total parenteral nutrition (TPN): Patients receiving long-term TPN without adequate biotin supplementation can develop a deficiency.

Comparison of Biotin Deficiency Symptoms in Adults vs. Infants


Symptom	Presentation in Adults	Presentation in Infants
Dermatological	Scaly, red periorificial rash, dermatitis, dry skin.	Periorificial rash, eczema, seborrheic dermatitis, and increased susceptibility to fungal infections like candidiasis.
Hair	Hair thinning, alopecia, or brittle hair.	Total alopecia (complete hair loss), fine and brittle hair.
Nails	Brittle, thin, or ridged nails.	Brittle nails.
Neurological	Depression, lethargy, paresthesias (pins and needles), hallucinations, and in severe cases, seizures.	Hypotonia (weak muscle tone), lethargy, seizures, and developmental delay.
Other	Fatigue, muscle pain, nausea, and loss of appetite.	Feeding difficulties (vomiting, refusal to eat), respiratory issues (stridor, apnea), and sensorineural hearing loss.

Treatment and Management

Identifying and treating biotin deficiency early is crucial to prevent irreversible neurological damage, especially in infants with inherited disorders. The primary course of treatment for an acquired deficiency often involves oral biotin supplementation. The appropriate amount can vary depending on the severity of the deficiency and the underlying cause.

Dietary management is also key. Incorporating biotin-rich foods into the diet can help maintain adequate levels for most people. Excellent dietary sources include cooked egg yolks, liver, legumes, and nuts. In cases where a dietary or lifestyle factor is the cause, such as high raw egg white consumption or chronic alcohol use, these factors must be addressed. Lifelong biotin supplementation is typically required for individuals with inherited biotinidase deficiency. For those with acquired deficiency, supplementation may be temporary until levels are restored. Biotin supplementation for deficiency is an effective, evidence-based therapy.

Conclusion

While overt biotin deficiency is a rare occurrence in the general population, understanding its wide-ranging symptoms is important, especially for at-risk individuals. The signs, which affect the hair, skin, and nervous system, often appear gradually. Early recognition and treatment with biotin supplementation, in conjunction with addressing the root cause, can effectively reverse many symptoms and prevent long-term complications. Anyone experiencing these symptoms should consult a healthcare professional for an accurate diagnosis and treatment plan. A balanced diet and mindful lifestyle choices are the best preventative measures for maintaining healthy biotin levels.

Frequently Asked Questions

The initial signs of biotin deficiency often appear gradually and can include subtle hair thinning, fatigue, and a red, scaly rash around the mouth, nose, and eyes.

Severe biotin deficiency is very rare in healthy individuals who eat a balanced diet. However, marginal deficiency can occur in pregnant women, and inherited conditions like biotinidase deficiency are also a cause.

Yes, in severe and untreated cases, biotin deficiency can lead to neurological issues, including depression, hallucinations, lethargy, paresthesias (pins and needles), and even seizures.

Treatment typically involves oral biotin supplementation. The appropriate amount and duration depend on the severity and cause of the deficiency. For inherited disorders like biotinidase deficiency, treatment is often lifelong.

Good dietary sources of biotin include cooked egg yolks, organ meats (like liver), legumes, nuts and seeds, sweet potatoes, and mushrooms.

Raw egg whites contain avidin, a protein that binds to biotin and prevents its absorption in the gut. Cooking the eggs denatures avidin, so cooked eggs do not pose this risk.

With appropriate biotin supplementation, many symptoms can begin to improve within a few weeks. Skin rashes often resolve within weeks, and hair regrowth can take a few months.