Biotin deficiency is caused by inflammatory bowel diseases that impair the absorption of the vitamin, special dietary disorders with the consumption of raw eggs (excess avidin – a vitamin B7 blocker protein), magnesium deficiency, smoking, alcohol, treatment with broad-spectrum antibiotics, sulfonamides, and anticonvulsants. Hypovitaminosis B7 has also been noted in individuals with congenital genetic defects of the biotinidase gene or other genes involved in biotin metabolism. Deficiency of water-soluble vitamin B7 (vitamin H) – manifested by dry skin, seborrheic dermatitis, dermatitis around the eyes, nose, mouth, ears and groin, impaired nail growth, slow healing of skin cuts, atopic dermatitis, striations, splitting, brittle nails and alopecia (diffuse and androgenic form). Alopecia occurs when hair follicles die and leads to hair loss. The human proteome contains 51 proteins involved in biotin metabolism. In particular, D-biotin-dependent carboxylases play an important role in the metabolism of fatty acids, amino acids, carbohydrates, cell division and growth, incl. keratinocytes and hair follicle cells. The molecular mechanisms of the effects of D-biotin on the skin and its appendages may involve various growth factors: regulation of the signaling pathways of growth factors (IGF-1, FGF, KGF, HGF, VEGF, SIRT-1, Wnt and beta-catenin) has been shown. Hair follicle stem cells cause the cyclical growth of hair follicles. Growth factors are involved in the activation of stem cell growth by D-biotin; activation of the Wnt/β-catenin signaling cascade leads to the activation of cyclin D1 proteins (initiates DNA synthesis and leads to increased viability of hair follicles. The results of fundamental and clinical studies confirm the prospects of using biotin in dermatology for the treatment of diseases of the skin, hair and nails, incl. alopecia of various origins (androgenic, focal, diffuse). The results of the studies indicated that biotin was well tolerated, and there was no risk of hypervitaminosis even when taking megadoses (hundreds of milligrams).
