The role of Biotin in hair growth

Have you seen the hype around Biotin for hair and nail growth on social media? It seems like everyone is talking about it! But the real question is - does it live up to the buzz? We will assess the actual evidence available in the literature to see how biotin promotes hair and nail growth. Get ready to be amazed by the facts!

What does biotin do in our bodies?
Biotin is also called Vitamin B7 (one of the 8 vitamin B complexes) or Vitamin H (H represents Hair und Haut, the German word for "Hair and skin"). Biotin is a water-soluble vitamin, and among many functions, one of the most important roles of Vitamin B7 is to convert the food we consume into energy, which means it helps to break down the carbohydrates, protein, and fats in our bodies into energy.

How much biotin is required by our body?
As per the Food and Nutrition Board of the Institute of Medicine - about a daily intake of 40 mcg/day is required to maintain good health. Biotin deficiency is rare in individuals consuming a normal balanced diet.

What are the sources of biotin?
Biotin can be acquired through -
Food - egg yolk, liver, cereals (wheat, oats), vegetables (spinach, mushroom), sweet potato, almonds and rice. Dairy items and breast milk also contain biotin.
Gut bacteria - Humans cannot synthesize biotin of their own but microorganisms (Bacteria) present in our intestine can make biotin for us.

What decreases the levels of biotin in our body?
Lack of biotin in individuals consuming a balanced diet has never been reported. Deficiency of biotin is a rare event and can be seen in the following circumstances -
Genetics - Some babies are born without the ability to produce biotin due to a lack of the biotinidase enzyme.
Gastrointestinal disorders like inflammatory bowel syndrome may impair nutrient absorption in the gut.
Drugs like long-term consumption of broad-spectrum antibiotics can change gut bacteria, and epilepsy drugs - carbamazepine, phenytoin, and phenobarbital can interfere with the absorption of biotin by our body. Isotretinoin, usually given for acne can also reduce levels of biotin.
Pregnancy, lactation, smoking, and long-term alcohol use can increase the metabolism of biotin, resulting in deficiency and necessitating supplementation.

So, what happens if there is a deficiency of biotin in our body?
When there is a deficiency of biotin in our blood, it can lead to various symptoms that are primarily related to our nervous system and the deeper layer of skin known as the dermis. These symptoms include hair loss (alopecia), eczema, conjunctivitis, lethargy, seizures, and loss of vitality and muscle strength.

What is the role of biotin in hair and nail growth?
The interesting thing is, biotin's efficacy in normal individuals has not been studied. However, research has shown that biotin supplementation is helpful in individuals with proven biotin deficiency or pathological problems of hair or nails. In a review of such 18 cases, biotin supplementation led to improvements in neurological, hair, and nail issues.
Furthermore, a study of 541 women with hair fall issues found that 38% had low biotin levels. Of these females, 11% had factors directly linked to biotin reduction, such as isotretinoin, antibiotics, anti-epileptics, GI disease, or co-existing seborrheic dermatitis. Additionally, laboratory studies have shown that biotin does not affect the multiplication of normal hair follicles.


It is widely believed that biotin can help with the growth of hair and nails. However, there is no conclusive evidence to support this claim. It is more likely that a person experiencing hair loss is deficient in other nutrients such as iron, folic acid, vitamin D, and vitamin B12, rather than solely lacking in biotin. In the real world, hair fall is usually caused by multiple factors and not just a single reason.

What happens if you take more biotin than required?
Excessive intake of biotin is not found to be toxic as it is a water-soluble vitamin. The excess is excreted in urine. It's crucial to understand that laboratory tests can be significantly impacted by high levels of biotin in the bloodstream. This can lead to falsely elevated levels of thyroid, vitamin D, and DHEAS (a sex hormone).

To conclude, while biotin is essential for our health, the deficiency of biotin in normal healthy individuals is not common. There is limited evidence supporting its role in hair and nail growth. Hair loss is often multifactorial, and relying solely on biotin may overlook other crucial factors and prevent timely management of hair fall.

Inputs by Dr. Anuradha Jindal, MD dermatology, Fellowship in Aesthetic dermatology, Chicnutrix