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Biotin (Vitamin H) : What Does the Science Say?

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August 18, 2021
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Akshay ChopraFounder - We R Stupid
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Biotin (also known as vitamin B7 or vitamin H) is a water-soluble vitamin that serves as an essential cofactor for carboxylase enzymes in multiple metabolic pathways, that catalyse critical steps in the metabolism of fatty acids, glucose, and amino acids(Click here to know more).

By the 1920s, it became apparent that ‘water-soluble B’ (vitamin B) is not a single substance.Various terms were proposed for these water-soluble vitamins, but vitamins B1 and B2 were most widely used. Although vitamin B1 proved to be a single chemical substance (thiamin), vitamin B2 was ultimately found to be a complex of several compounds, including niacin, biotin, and pantothenic acid. Biotin and pantothenic acid are vitamins which occurred somewhat later as a result of efforts to understand microbial growth factors (Click here to know more).


Because of to its relatively low cost and abundance of availability in cosmetic products, Vitamin H has become the new trend & go-through supplement for consumers wishing to have longer, healthier hair and nails (Click here to know more).


Most vitamin h in foods is bound to protein, although some dietary biotin is in the free form. Gastrointestinal enzymes like, proteases and peptidases break down the protein-bound forms of ingested biotin into biocytin and biotin-oligopeptides, which undergo further processing by biotinidase, an enzyme, in the intestinal lumen to release free biotin. The free biotin is then absorbed in the small intestine, and most biotin is stored in the liver (Click here to know more).

Current recommendations for biotin by the Institute of Medicine state that the daily adequate intake (AI) for adults is 30mg/day. Most healthy individuals meet these requirements through a well-balanced diet, though many still take up to 500–1,000μg of biotin supplementation daily , which of course is quite unnecessary.No tolerable upper intake has been specified in the dietary reference intakes.

Although no major toxicities of excess biotin have been reported, data on the actual benefit of biotin’s effect on hair and nail growth is limited. Moreover, outside the setting of pregnancy, malnutrition, medication effects, and biotinidase deficiency in children, reports of low biotin levels have rarely been cited (Click here to know more).

Biotin is widely distributed in foods. Foods relatively rich in biotin include egg yolk, liver, whole cereals, fish, seeds, nuts and some vegetables like sweet potatoes . Infants consuming 800mL of mature breast milk per day ingest app. 6ug of biotin. Dietary biotin is generally 100% bioavailable (Click here to know more).

Vitamin H rich foods


Signs of biotin deficiency may be observed in individuals with deficiencies in biotin, HLCS (Holocarboxylase synthetase), and biotinidase and in individuals consuming large amounts of raw egg white; the biotin-binding protein avidin in raw egg white causes a substantial decrease in the bioavailability of biotin . Cooking denatures avidin, making it unable to interfere with biotin absorption . A rare biotin transporter defect has been identified that may also cause severe biotin deficiency.

Biotinidase deficiency is a rare disorder that prevents the body from releasing free biotin, leading despite normal intake. Without treatment, biotinidase deficiency produces neurological symptoms, and profound biotinidase deficiency can lead to coma or death .Biotin appears to be readily absorbed through both normal supplemental and dermal (ointment/cream/gel) form.

Supplementation of 900mcg biotin appears to be sufficient to increase circulating biotin concentrations in otherwise healthy adults without a deficiency .

Genetic biotinidase deficiencies require timely intervention and lifetime supplementation to avoid severe neurological disorders. The disorder also requires lifetime biotin supplementation at 5-20mg daily due to drastically reduced biotin retention.Biotinidase deficiency has been reported to have a prevalence of 1 in 112,271 (profound deficiency of less than 10% biotinidase activity) and 1 in 129,282 for partial deficiency (10-30% biotinidase deficiency).If left untreated severe neurological symptoms develop, including seizures, ataxia, and mental retardation(Click here to know more).

Biotin catabolism is accelerated in pregnant and lactating mothers. Likewise, biotin deficiency might be encountered in smokers, users of certain anticonvulsant medicines, and after consumption of large doses of alpha lipoic acid(Click here to know more).

The signs and symptoms of biotin deficiency typically appear gradually and can include thinning hair with progression to loss of all hair on the body; scaly, red rash around body openings (eyes, nose, mouth, and perineum); conjunctivitis; ketolactic acidosis (which occurs when lactate production exceeds lactate clearance) and aciduria (abnormal amounts of acid in urine); seizures; skin infection; brittle nails; neurological findings (e.g., depression, lethargy, hallucinations, and paresthesias of the extremities) in adults; and hypotonia, lethargy, and developmental delay in infants. The rash and unusual distribution of facial fat in people with biotin deficiency is known as “biotin deficiency facies” (Click here to know more).

Alpha-lipoic acid (ALA) appears to reduce the activity of some biotin-dependent enzymes in the liver. This occurred in a manner that was reversible with biotin supplementation. ALA-induced suppression of biotin-dependent enzyme function did not appear to cause overt physiological dysfunction (Click here to know more).

biotin supplements



Studies have shown positive effects of Vitamin H supplementation on lipid profile. A study on the effect of biotin supplementation (0.9 mg/day) on plasma lipids was carried out in 40 men and women, age 30 to 60 years, for 71 days, found a reduction in triglycerides and total cholesterol levels.

Another study investigated the effect of biotin administration on plasma lipids, as well as glucose and insulin in type 2 diabetic and non diabetic subjects. Eighteen diabetic and 15 non diabetic subjects aged 30-65 were divided into two groups and received either 15 mg of biotin or placebo for 28 days.

Biotin supplementation was shown to reduce triglycerides and VLDL in both diabetic and nondiabetic subjects without any changes in total cholesterol or insulin sensitivity.

Biotin supplementation has proven to be beneficial for diabetics. Research has shown the benefits of biotin on the function and proportion of beta cells and its effects on the prevention of insulin resistance, in rats .

Smaller human studies have also shown the benefits of high dose biotin supplementation diabetic patients suffering from diabetic neuropathy .

In another study the therapeutic efficacy of biotin was evaluated in 43 patients with non-insulin dependent diabetes mellitus. The biotin concentration in the patients was significantly lower than that in the 64 healthy control subjects and inversely correlated with the fasting blood glucose level. These observations suggest that the biotin administration reduces abnormal glucose metabolism in diabetic patients.


It has been known since a long time that biotin deficiency causes alopecia and a scaly dermatitis in the body. Biotinidase deficiency, causes biotin deficiency, probably as a consequence of unpaired intestinal absorption, cellular salvage, and renal reclamation of biotin(Click here to know more).

A study on four lung cancer patients undergoing chemotherapy, who had developed skin rashes, showed that, administration of biotin reduced the severity of the skin rash.


In instances that biotin deficiency occurs, of which there are numerous possible causes, administration of biotin appears to be able to restore hair loss that occurs with biotin deficiency (Click here to know more).


The initial studies on biotin on its effects on nails, started from a study on horses . The study showed that biotin supplementation on horses with weak hoof, led to improvement in the hardness, integrity and conformation of the hoof horn were observed in all cases.

There have been 3 human studies, which showed the benefits of biotin supplementation on brittle fingernails. Though most of them were old and similar studies:

In a study , 32 women were placed into three groups: group A consisted of 10 control subjects with normal nails, group B comprised eight patients with brittle nails studied before and after biotin treatment, and group C was 14 patients with brittle nails in whom the administration of biotin did not coincide exactly with the initial and terminal clipping of the nails.

The thickness of the nails in group B increased significantly by 25%. In group C, the increase was 7%. Splitting of the nails were reduced in groups B and C and the irregular cellular arrangement of the dorsal surface of brittle nails became more regular in all nails of group B and in 8 of 11 nails of group C.

In another study , 71 patients were treated with a daily oral dose of biotin of 2.5 mg. Out of the 45 cases which finally could be evaluated, 41 (91%) showed definite improvement with firmer and harder finger nails after an average treatment of 3-8 months. In 4 of the 45 patients (9%), the improvement was questionable. 

Another study demonstrated a 25% increase in nail plate thickness in patients with brittle nails who received biotin supplementation. Analysis of over a six-month period revealed 44 patients with this condition who had been prescribed the B-complex vitamin biotin. Of these, 35 who took daily supplementation were subjectively evaluated. 22 of 35 (63%) showed clinical improvement and thirteen (37%) reported no change in their condition.

hair loss supplements


Acc. to research compilation , “Biotin has been seen as the go-to vitamin for beauty ever since one pilot study in women with brittle nails showed supplementation to be beneficial. It is currently being marketed for improving nail, skin, and hair aesthetics. These claims, however, were not followed up scientifically so there is not much evidence to support biotin’s role here. It can plausibly have these actions mechanistically, but there is simply not much evidence that can be used as support.”

A systematic review study analysed the literature on biotin efficacy in hair and nail growth. Researchers found, 18 reported cases of biotin use for hair and nail changes. In all cases, patients receiving biotin supplementation had an underlying pathology for poor hair or nail growth.

Researchers concluded that, “though the use of biotin as a hair and nail growth supplement is prevalent, research demonstrating the efficacy of biotin is limited. In cases of acquired and inherited causes of biotin deficiency as well as pathologies, such as brittle nail syndrome or uncombable hair, biotin supplementation may be of benefit.” However, researchers proposed that these cases are uncommon and that there is lack of sufficient evidence for supplementation in healthy individuals.

Researchers also found that, for patients with inherited enzyme deficiency, larger doses of biotin supplementation are recommended (from 10,000 to 30,000ug/day). Those with brittle nail syndrome and other underlying hair pathologies, such as uncombable hair syndrome, require much lower doses of biotin supplementation ranging from 300 to 3,000ug/day.

Moreover, only 1 case in the literature has measured the levels of biotin in normal individuals that had complaints of hair loss . In this study of 541 women (age range between 9 and 92 years), biotin deficiency was found in 38% of women complaining of hair loss. However, of those women, 11% were later found through patient history (use of antibiotics, antiepileptics, isotretinoin, or GI disease) to have a reason for the underlying deficiency and 35% had co-existing dermatitis, suggesting a multifactorial cause for hair loss.

The researchers clearly stated that, “The custom of treating women complaining of hair loss in an indiscriminate manner with oral biotin supplementation is to be rejected, unless biotin deficiency and its significance for the complaint of hair loss in an individual has been demonstrated on the basis of a careful patient history, clinical examination, determination of serum biotin levels, and exclusion of alternative factors responsible for hair loss.”

Acc. to Harvard research , “Despite the inconclusive evidence, biotin supplements remain popular. Between 1999 and 2016, the proportion of supplement users increased by nearly thirty fold. In November 2017, the U.S. Food and Drug Administration (FDA) issued a warning based on reports of biotin supplements interfering with laboratory blood tests, causing incorrect results. High doses have produced either falsely elevated or decreased blood levels, depending on the test. This has affected lab results of certain hormones, such as thyroid hormone and vitamin D, as well as a biomarker for heart attacks called troponin. Case reports of this occurrence showed people taking biotin amounts much higher than the AI level (30 micrograms daily or 0.03mg) but in doses commonly found in supplements (10-300mg). Biotin is often added to multivitamins and hair/nail/skin supplements.”

With tons of studies in front of you, it’s clearly proven that Biotin (Vitamin H) as a supplement is quite useless for most people, for the purpose they are using it, i.e. mainly skin, hair and nail health. It’s a heavily marketed, overhyped supplement, which has been sold primarily for profits, and for the simple reason that it’s in demand, not because it works. Rest, is your choice, because it’s your money, and your health.

Akshay Chopra

Akshay Chopra is a renowned fitness professional, a speaker , a writer and the owner of Indias research based platform, Werstupid. He has been transforming lives, and has addressed many a people with motivational words. Known as the Encyclopaedia of Fitness Industry, his knowledge is unparalleled.

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