Biotin – a magic pill or good marketing?

The word biotin carries with it spectacular promises of shiny hair, strong nails and smooth skin. But are there scientific grounds for these claims or is it just a marketing trick?

What is biotin?

Biotin, otherwise known as vitamin B7, is a vitamin of the B complex. Like other B complex vitamins, biotin is soluble in water and is thus not stored in the body, which is why it’s necessary to consume it in food. Luckily, it’s found in small amounts in various foods such as boiled eggs, nuts, legumes, cereals, bananas and many other ingredients consumed on a daily basis. Although the body cannot synthesize biotin on its own, the average daily intake of biotin through food is 35 – 70 μg, which satisfies the recommended daily intake of 30 μg. Biotin supplementation is therefore not indicated for use in healthy individuals.

The role of biotin

Like other B complex vitamins, biotin plays an important role in the metabolism of amino-acids, fatty acids and glucose. It also takes part in other processes such as gene regulation, cell signalling and replication. Biotin is a cofactor for an enzyme called carboxylase and binds carbon dioxide in reactions in which this enzyme is present. Due to its role in protein synthesis, specifically keratin synthesis, it’s considered an important contributor to hair, nail and skin health.

Biotin deficiency

Acquired biotin deficiency, which is a deficiency caused by insufficient biotin intake, is considered very rare. It’s found in groups at risk such as pregnant people, patients with diseases affecting nutrient absorption (e.g. Crohn’s disease) and patients who consume alcohol on a regular basis. Acquired biotin deficiency can also be a result of other medication interfering with biotin absorption, such as anticonvulsants and isotretinoin.

Congenital biotin deficiency is determined by a recessive gene which causes a lack of enzymes necessary to properly metabolise biotin, such as holocarboxylase synthetase and biotinidase. Inherited biotin deficiency is usually detectable from an early age.

Deficiency symptoms are similar in both acquired and congenital deficiencies; they include alopecia, rashes, nail changes, seborrheic dermatitis as well as neurological symptoms such as lethargy, depression, ataxia and seizures.

Biotin as a food supplement

In the last couple of years, additional intake of biotin in the form of a supplement has been more and more common. Capsules or tablets containing a dose of biotin three times larger than the recommended daily dose are easily available in stores and over the internet, oftentimes accompanied by promises of healthier hair, nails and skin. However, no research conducted so far has been able to support these claims. A substantial effect of biotin on the appearance of hair, skin and nails has only been noticed in patients with pathological conditions affecting keratin structures, such as the aforementioned biotin deficiencies or brittle nail syndrome. In healthy individuals with normal blood levels of biotin, an increased intake did not result in any changes in hair, skin or nail appearance.

Although an increased biotin intake isn’t harmful in itself because any surplus can be excreted through urine, an elevated level of biotin can interfere with other laboratory tests. Biotin intake has thus been linked to false results when measuring thyroid hormone levels, which can lead to a wrongful diagnosis of hyperthyroidism. Likewise, biotin supplements can also affect human chorionic gonadotropin (hCG) measurements, which is both an important tumor marker and a pregnancy marker.

Should biotin be supplemented?

Despite the vital role of biotin in keratin synthesis, no connection has been found between increased biotin intake and the appearance of hair, skin and nails in healthy individuals. Although the intake of biotin supplements is not harmful in itself, it can affect other laboratory tests and be detrimental to one’s health in that way, so it’s important to always consult one’s doctor regarding biotin supplementation.