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 intestinal flora of the body. 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 sources of biotin and therefore 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 has been found to be associated with falsely high or low laboratory test results. According to the FDA a number of 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, 30mcg/day to be an adequate intake of biotin for adults in the U.S. population.

Normal functions supported by biotin

biotin hair growthBiotin 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 above-mentioned signs and symptoms of biotin deficiency suggest it has an impact on hair health, the efficacy of biotin supplements for hair, skin, and nails to tackle these conditions remains controversial. This is largely due to insufficient and inconclusive data from any large-scale studies. 

However, multiple case reports do exist that report beneficial outcomes of biotin supplements when 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, that exhibited premature graying of the hair, with a control population. The researchers evaluated and compared biotin levels between the two groups and found lower levels of biotin without any obvious 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, among whom ten had a diagnosed genetic biotin deficiency, and the remaining eight suffered from alopecia that improved after biotin supplementation. All these 18 subjects were introduced to daily supplementation of biotin and once treated all demonstrated clinical improvement over a variable period.

Does biotin support hair growth?

From the above discussion, it can be fairly concluded that evidence of the use of biotin supplements alone for the promotion of hair growth does not qualify for enough merit. However, trichologists do recommend healthy eating and other dietary supplements that in combination act as synergy with biotin and impart beneficial effects on hair health.




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