Scientific Name(s): d-(+)-Biotin, hexahydro-2-oxo-1H-thieno[3,4-d]imidazole-4-pentanoic acid
Common Name(s): Biotin, Coenzyme R, Factor S, Vitamin B7, Vitamin H, W factor
Medically reviewed by Drugs.com. Last updated on Apr 14, 2022.
Biotin has been used to treat male pattern baldness and has been an ingredient in hair- and skin-conditioning products, although evidence to support its use in the prevention of hair loss or in brittle nails is lacking. Limited clinical studies have evaluated the effects of supplemental biotin in diabetes, with high doses used in multiple sclerosis, as well.
There is no evidence that biotin supplementation at the recommended daily intake (RDI) is required or effective, except in cases of biotin deficiency. A healthy diet will include the recommended biotin 30 mcg/day intake required by adults. Very high doses (10,000 times the RDI) of 100 to 600 mg/day have been used in preliminary studies for up to 2 years to manage symptoms and disease progression of multiple sclerosis.
Contraindications have not yet been identified.
Safety and efficacy for dosages above those found in foods are unproven and should be avoided.
Anticonvulsant medicines may lower biotin status. Biotin consumption has been shown to interfere with some laboratory assay results, including troponin, thyroid function, parathyroid, 25-hydroxy vitamin D, follicle stimulating hormone, luteinizing hormone, cortisol, C-peptide, prolactin, and testosterone tests.
Few adverse reactions have been reported in limited clinical studies.
Biotin as used in cosmetic preparations is considered safe. Limited studies suggest reproductive and developmental toxicity may be associated with biotin intake during pregnancy.
Biotin is a water-soluble B-vitamin found naturally in many foodstuffs, although the content varies widely. Biotin is highly concentrated in liver (100 mcg per 100 g), whereas most other meats contain small amounts (1 mcg per 100 g). Leafy green vegetables, peanuts, Saskatoon berries, and raw egg yolk also contain large amounts of biotin.Food and Nutrition 1998 Egg whites, however, contain the protein avidin, which binds very tightly to biotin, reducing its bioavailability.Food and Nutrition 1998 A usual Western diet contains adequate amounts of biotin.Flume 2001 Biotin is also synthesized by intestinal microflora; however, how this contributes to the amount of biotin available in the body is unclear.Flume 2001, Food and Nutrition 1998, Said 2011
Biotin was identified in 1927 and recognized as a vitamin some 40 years later.Food and Nutrition 1998 It was called vitamin H, based on the German words for "hair" and "skin," haar and haut. In 1985, the US Food and Drug Administration withdrew support for the use of biotin for the treatment of male pattern baldness.Debourdeau 2001
Biotin is a heterocyclic, sulfur-containing monocarboxylic acid, and a coenzyme for carboxylase enzymes. It is also involved in gluconeogenesis, the synthesis of fatty acids, and the metabolism of fats and amino acids. Proteolysis by biotinidase is required prior to absorption because most biotin in foods is bound to protein.Food and Nutrition 1998, Fugate 2012, Li 2012, Lin 2011, Wolf 2011
Uses and Pharmacology
Biotin was included in vitamin/mineral supplementation in a study in autism. Biotin, along with vitamin K, was associated with improved Parental Global Impressions (revised) scores on regression analysis.(Adams 2011, Zaffanello 2003)
Rats fed a biotin-deficient diet showed reduced growth, reduced organ weight, loss of body fat, skin problems, and hair loss.(Flume 2001)
Biotin deficiency has been noted in individuals who consume raw egg whites over a long period of time, as well as in those in whom parenteral nutrition is biotin deficient and in patients with autosomal recessive inherited biotinidase deficiency. Long-term alcohol use has also been associated with biotin deficiency.(Daniells 2010, Food and Nutrition 1998, Ogundele 2011, Said 2011, Wolf 2012) Hair thinning, loss of hair color, and a scaly skin rash, as well as childhood acrodermatitis, are the most commonly reported symptoms.(Gehrig 2010, Wolf 2012) Neurological symptoms, including depression, lethargy, hallucinations, and paresthesia of the extremities, are also associated with biotin deficiency.(Flume 2001, Food and Nutrition 1998, Raha 2011, Wolf 2012)
Biotinidase deficiency should be managed under the guidance of a health care provider.
Animal studies have established an association between biotin deficiency and impaired glucose utilization.(Báez-Saldaña 2004, Zhang 1997) Possible mechanisms for biotin activity and glycemia improvement include increased utilization of glucose for fat synthesis, increased synthesis of glycogen, and stimulation of insulin secretion in the pancreas.(Romero-Navarro 1999)
Limited clinical studies have evaluated the effects of supplemental biotin in diabetes, finding improved glucose control.(Báez-Saldaña 2004, Maebashi 1993, Revilla-Monsalve 2006) Many other studies have investigated combinations of chromium and biotin, making it difficult to attribute results to either substance.(Albarracin 2008) Chromium is widely used by people with type 2 diabetes. See also Chromium monograph.
Fingernails and hair
Limited, older clinical studies with subjective measures and 1 study with objective measures indicated a potential role for biotin in improving brittle fingernails.(Hochman 1993) However, quality clinical studies supporting this application are lacking.
Hair loss is a symptom of biotin deficiency; however, there is no evidence to support the use of biotin supplementation to prevent hair loss.
Biotin supplementation in patients undergoing hemodialysis has been evaluated in a small study with an end point of reduced muscle cramps.(Oguma 2012)
The role of biotin in fatty acid synthesis and neuronal energy production is thought to support myelin repair and protect against axonal degeneration. Limited data have demonstrated a therapeutic response to high-dose biotin in neurometabolic disease, optic neuropathies, and leukoencephalopathy. Safety and efficacy in adults with progressive multiple sclerosis (MS) has also been explored with high doses (10,000 times the recommended daily intake [range, 100 to 600 mg/day]).(Sedel 2015, Tourbah 2016) In one small open-label pilot study (n=23), some clinical improvement was observed in the majority (91.3%) of patients with benefits that usually appeared within the first 2 to 9 months of treatment. The median dose was 300 mg/day given in 3 divided doses. Most patients had symptoms related to spinal cord involvement, whereas 4 presented with prominent optic nerve involvement and 1 exhibited homonymous hemianopia with optic radiations. Improvement in other symptoms observed in at least 2 patients were related to fatigue, swallowing, dysarthria, sensory signs, gait ataxia, and urinary dysfunction. No effect was noted on relapses; doses were well tolerated.(Sedel 2015) In a larger 1-year double-blind, randomized, placebo-controlled study (N=154) conducted in patients with primary or secondary progressive MS, also known as the MS-SPI trial, biotin 300 mg/day provided a significant improvement in MS-related disability at 9 and 12 months compared to placebo (14.9% vs 0%, respectively; P=0.009). More patients achieved this outcome who were not concomitantly taking fampridine (20.3% vs 2.3%) or who had lower baseline disability scores (21.4% vs 9.3%, respectively). Benefit continued through the 1-year open-label extension phase for patients initiated on biotin as well as those initiated on placebo. Not all secondary outcomes were achieved; however, at year 2, severity scores were significantly better in the biotin group and progression had stopped in placebo patients after they were switched to biotin in the extension phase. High-dose biotin was well tolerated and adverse event incidence was similar between groups.(Tourbah 2016) The SPI-2 trial replicated the MS-SPI trial in a larger, international cohort (N=642) and demonstrated no significant therapeutic benefit at the 15-month follow-up in the overall population or in any of the prespecified subgroups. Similarly, no significant difference was observed between the high-dose biotin and placebo groups in adverse events.(Cree 2020)
Reversibility of factor X inhibitor
The incorporation of biotin into idraparinux (an anticoagulant medication currently in development) to assist avidin's ability to reverse factor X inhibitor activity has been reported.(Paty 2010) Exploitation of the bonding between avidin and biotin in targeted therapy, including radioimmunotherapy, is being investigated and is widely used in medical research applications.(Lesch 2010)
There is no evidence that biotin supplementation at the recommended dietary intake (RDI) is required or effective, except in cases of biotin deficiency. A healthy diet will include the recommended biotin 30 mcg/day intake required by adults. Doses of up to 200 mg orally and 20 mg intravenously have been used to treat biotin deficiency.Food and Nutrition 1998
Very high doses of 300 mg/day (range: 100 to 600 mg/day) given in 3 divided doses for up to 2 years have been shown in preliminary studies to improve disease progression and some other symptoms of adults with progressive multiple sclerosis. These doses are 10,000 times the usual RDI.Sedel 2015, Tourbah 2016
Pregnancy / Lactation
Safety and efficacy for dosages above those found in foods are unproven and should be avoided. An adequate daily intake of biotin 30 mcg during pregnancy and 35 mcg during breast-feeding is recommended by the Food and Nutrition Board of the Institute of Medicine.Food and Nutrition 1998
Despite studies indicating that up to half of pregnant women exhibit decreased urinary excretion of biotin, suggesting lower circulating biotin levels, there is no evidence for increased biotin intake during pregnancy.Food and Nutrition 1998 Studies in animals (rodents and poultry) by a single group of researchers suggested that a marginal deficiency of biotin during pregnancy may have teratogenic effects, possibly due to an increased biotin requirement in proliferating cells. Fetal malformations in rats have been observed due to biotin deficiency, including cleft lip and palate and impaired skeletal long bone growth.Mock 2005, Mock 2009, Zempleni 2009
Limited studies suggest reproductive and developmental toxicity may be associated with biotin intake during pregnancy in rodents. In rats, decreased fetal, uterine, and placental weights were observed when biotin was administered by subcutaneous injection in reproductive studies.Flume 2001
An increased milk yield has been demonstrated in cows fed biotin,Kinal 2011, Chen 2011 but high-dose biotin suppressed ovulation in lactating cows.Kinal 2011
Case reports of interactions are lacking. Reduced biotin levels have been noted among people taking anticonvulsant medications, including primidone, carbamazepine, phenobarbital phenytoin, and valproate. Mechanisms include decreased biotin absorption in the small intestine, increased biotin excretion, and decreased biotinidase activity.
Long-term administration of antibiotics may lead to a decrease in bacterial synthesis of biotin.(Food and Nutrition 1998, Said 2011, Zempleni 2009)
Interference with some laboratory assays has been documented with ingestion of biotin, including troponin, thyroid, parathyroid, 25-hydroxy vitamin D, follicle-stimulating hormone, luteinizing hormone, cortisol, C-peptide, prolactin, and testosterone. Health care providers need to communicate to the lab if their patient is taking biotin.(Biscolla 2017, FDA 2019, Piketty 2017, Stieglitz 2018)
Biotin in patient samples can lead to falsely low results for troponin and a missed diagnosis of heart attack. A list of troponin laboratory developers that have not addressed the biotin risk in their assays has been documented by the FDA.(FDA 2019)
Falsely reduced levels of thyroid stimulating hormone (TSH) were reported by 2 of the 4 diagnostic assays used resulting in reports of 37% and 94% below baseline; the latter result fell below the normal reference range. Other results that were significantly falsely affected and fell outside the limits of the normal reference range by at least one assay tool included parathyroid hormone (61% reduction), total T3, free T3, and N-terminal pro-brain natriuretic peptide. Calcium, ferritin, and prolactin results were not significantly impacted by biotin ingestion. Interference was found to be significantly different between biotinylated vs non-biotinylated assay methods (P=0.007) with 39% vs 0% interference, respectively.(Li 2017) Interference with thyroid lab tests has been documented using acute doses with biotin dietary supplementation of 10 mg in healthy volunteers; effects which disappeared within 24 hours. Excess biotin resulted in significantly altered false increases in free T4 and T3 levels (P<0.0001 each) when tested with competitive immunoassays, and significantly false decreases in levels of TSH (P<0.005) with immunometric assays. These results often, but not always, led to measurements outside the limits of the reference range.(Biscolla 2017) In addition misleading results for TSH, free T4, and free T3, an assay interference investigation conducted in patients with multiple sclerosis as well as healthy volunteers revealed that high-dose biotin (300 mg/day) had a major impact on other hormone levels.(Piketty 2017)
Clinically misleading results were observed for 25-hydroxy vitamin D, parathyroid hormone, follicle stimulating hormone, luteinizing hormone, cortisol, and C-peptide. Prolactin results were unaffected. Susceptibility of the assays to biotin interference was highly variable.(Piketty 2017) In another case, prolactin and total testosterone as well as several other hormone levels were reported as falsely affected in a euthyroid perimenopausal female who was initially misdiagnosed as having subclinical hyperthyroidism and a possible testosterone-secreting tumor.(Stieglitz 2018)
The FDA is warning that biotin can significantly interfere with certain lab tests and cause incorrect test results that may go undetected, possibly leading to inappropriate patient management or misdiagnosis.(FDA 2019)
Health care providers and patients should be aware that biotin is found in multivitamins (including prenatal multivitamins, biotin supplements, and dietary supplements for hair, skin, and nail growth) in levels that may interfere with lab tests; high levels of biotin may not be apparent just from the name of the supplement. Providers should talk with their patients about any supplements they may be taking, and if a lab test result doesn't correspond with a patient's clinical symptoms, biotin interference should be considered as a possible source of error.
Further information can be found at https://www.fda.gov/medical-devices/safety-communications/fda-warns-biotin-may-interfere-lab-tests-fda-safety-communication.
Few adverse reactions have been reported.Flume 2001, Rogovik 2010 A case report exists describing an instance of reversible eosinophilic pleuropericarditis in an elderly woman associated with use of high-dose biotin (10 mg/day) and vitamin B5 over a 2-month period.Debourdeau 2001
Biotin in blood or other samples taken from patients who are ingesting high levels of biotin from dietary supplements (including multivitamins; prenatal multivitamins; biotin supplements; and dietary supplements for hair, skin, and nail growth) can cause clinically significant incorrect lab test results. Some testing methods use biotin technology (eg, Troponin, hormone tests), using biotin to bind to specific proteins that are measured to detect health conditions. An increase in the number of reported adverse events, including one death, related to biotin interference with lab tests has been reported. If a lab test result does not correspond with a patient's clinical symptoms, biotin interference should be considered as a possible source of error.FDA 2017
Biotin as used in cosmetic preparations is considered safe.Flume 2001 Doses of up to 600 times the usual dietary intake have been used without signs of toxicity.Food and Nutrition 1998, Zempleni 2009
The oral median lethal dose for biotin in rats has been estimated to be more than 10 g/kg; it was not toxic in oral short- or long-term toxicity studies. Biotin was not associated with mutagenicity in bacterial tests.Flume 2001
Limited studies in rodents suggest reproductive and developmental toxicity may be associated with biotin intake during pregnancy. Decreased fetal, uterine, and placental weights were observed when biotin was administered by subcutaneous injection in reproductive studies in rats.Flume 2001
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