The role of biotin in hair growth

Biotin (B7) is one of the eight water-soluble vitamins of the vitamin B complex family. Out of these eight vitamins, all can be obtained through a balanced diet, except for biotin, which is solely produced by the body’s intestinal flora. 


In a healthy individual, no supplementation of biotin is necessary as the deficiency of this vitamin is rare in developed countries. Some of the best dietary biotin sources for your hair growth include egg yolk, meat, nuts, whole grain, bananas, soybeans, and mushrooms.


Almost no cases of severe biotin deficiency have been reported to date in individuals consuming a balanced healthy diet. Similarly, cases of biotin toxicity are also non-existent; however, high biotin intake is associated with falsely high or low laboratory test results. 


According to the FDA, several dietary supplements marketed for hair, skin, and nail benefits are documented to contain levels up to 650 times higher than the recommended daily intake of biotin. Whereas the studies report that 30mcg/day is an adequate intake of biotin for adults in the U.S. population.

biotin hair growth

Normal functions supported by biotin

Biotin is also known as vitamin H, which stands for Haar and Haut, meaning hair and skin in German. It primarily acts as a cofactor in processes that metabolize fatty acids, glucose, and amino acids. It is also well known for its action in histone modification, gene regulation, and cell signaling.  

B7 is also recognized to stimulate keratin production, a protein that is vital for hair growth and development.

Causes of biotin deficiency

Biotin deficiency can be both genetic or acquired. Genetic causes of biotin deficiency present early in life as severe dermatitis and hair loss, which may include the hair on the scalp, eyebrows, eyelashes, and general body hair. Acquired biotin deficiency can occur in conditions such as malabsorption, pregnancy, excessive consumption of alcohol, or prolonged use of antibiotics. Studies report that almost 50% of pregnant women have some intensity of biotin deficiency. On an estimate, one in every 140,000 individuals has a biotin deficiency, with symptoms typically observed within the first few months of life when the cause is genetic.

Signs of biotin deficiency include:

  • hair loss,
  • Scaly skin rashes, especially on the skin around the eyes, nose, and mouth,
  • Brittle nails,
  • Conjunctivitis,
  • Nausea and abdominal cramping,
  • Depression, confusion and memory problem,
  • Easy fatiguability,
  • Hallucinations(late sign),
  • Numbness and tingling of the arms and legs.

Although the signs mentioned above and symptoms of biotin deficiency suggest it impacts hair health, the efficacy of biotin supplements for hair, skin, and nails to tackle these conditions remains controversial. This is mainly due to insufficient and inconclusive data from large-scale studies.

However, multiple case reports exist on the benefits of biotin supplements used in children. One such study published in 2007 found that 3–5 mg of biotin a day improves hair health over 3–4 months in children suffering from uncombable hair syndrome.

A case–control study published in 2017 compared 52 subjects less than 20 years old with a control population that exhibited premature graying of the hair.

The researchers evaluated and compared biotin levels between the two groups and found lower levels of biotin without any apparent biotin deficiency in the groups suffering from premature grey hair.

Another review article published in 2009 evaluated the effects of biotin and its supplementation on human hair. They followed 18 participants, ten of whom had a genetic biotin deficiency, and the remaining eight suffered from alopecia that improved after biotin supplementation. All these 18 subjects were introduced to daily biotin supplementation and, once treated, demonstrated clinical improvement over a variable period.

Does biotin support hair growth?

The above discussion shows evidence that using biotin supplements alone to promote hair growth does not qualify for enough merit. Trichologists, on the other hand, suggest healthy eating and other nutritional supplements since they support the effects of biotin on hair health.

What types of biotin are there?

Biotin-rich foods

Biotin-rich foods are available in a variety of forms, including meat and poultry, fish, eggs, nuts and seeds, sweet potatoes, spinach, broccoli, cauliflower, yeast, egg yolks, oats, wheat germ, mushrooms, cheese, curds, cow’s milk, pork, beef, chicken, salmon, apples, bananas, tomatoes, carrots, lettuce, and potatoes.

Meat and poultry, such as beef and pork, are naturally high in biotin, as are fish like salmon and eggs. Nuts and seeds, such as almonds and walnuts, are also good nutrient sources, as are sweet potatoes, spinach, broccoli, and cauliflower. Yeast and egg yolks are also biotin-rich, as are oats, wheat germ, and mushrooms.

Cheese, curds, and cow’s milk are all good sources of biotin, as are pork, beef, and chicken. Finally, some fruits and veggies, like apples, bananas, tomatoes, carrots, lettuce, and potatoes, are also high in biotin.

Mega-B vitamins

Mega-B vitamins combine B vitamins, including biotin, zinc, vitamin C, and folic acid. These vitamins are taken together to provide maximum benefits for health and beauty. Biotin is a B vitamin produced naturally in the body, which plays an essential role in cell metabolism and energy production. It is usually supplemented to get an extra boost. Zinc, Vitamin C and Folic Acid are water-soluble vitamins that are taken together to enhance the benefits of biotin. They all aid in cell development, the metabolism of fats, and energy production. Compared to the other B vitamins, biotin is the only one produced by the body, and it is necessary to supplement it to get enough. A mega-B vitamin combination benefits those who have dietary restrictions or need an extra biotin boost.


In conclusion, biotin plays an essential role in healthy hair growth. The vitamin works to keep the scalp hydrated, counter dryness and breakage, and boost collagen production for thicker hair. Although dietary biotin is enough for most individuals, more severe hair loss might require additional supplementation.

Seeing a Trichologist or doctor before taking any supplements is highly recommended to determine a specific course of treatment that might help with hair growth. If you want to know what could be causing your hair loss, take our quiz and gain insight into possible causes that can be addressed through lifestyle changes or treatments. Remember to get advice from medical professionals before undergoing any course of treatment!


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