What is biotin?

Biotin, also known as Vitamin H or Vitamin B7, has made steep headway in the beauty industry.  It's been advertised as a magic pill to give individuals long and healthy hair, shiny nails, and beautiful skin.  There are clear grey areas regarding biotin: some professionals claim it is redundant as the body naturally produces biotin by some bacteria present in the body.  On the whole, most biotin is attained through diet.  Any excess biotin introduced into the body is immediately excreted as it is water-soluble, thus, it is not stored.  On the other hand, those that have adhered to biotin supplements claim their beauty has enhanced by ten fold.  As a result, I couldn't help but nose-dive into publications to figure out the science which underpins biotin.

DISCLAIMER: Take my review and research with a pinch of salt.   Talk to a GP or dermatologist for further information about any skin care products or supplements you want to introduce into your regime or concerned about.  I am not a doctor or cosmetic chemist. This post is not meant to substitute a healthcare professional or professional healthcare advice.  

Biotin is also known as Vitamin B7, and previously was referred to as Vitamin H and coenzyme R. Biotin is produced by bacterium in the intestines and is therefore, naturally occurring in the body. Alongside this, it can obtained through diet or supplements.  Biotin is one of the water-soluble vitamins.  (1) A deficiency in biotin can potentially lead to alopecia, scaly skin, and defects of the central nervous system. It is a coenzyme or cofactor that aids in catalysis of metabolic reactions such as gluconeogenesis (generating glucose from non-carbohydrate products such as lactate, pyruvate, and amino acids), fatty acid synthesis, and amino acid catabolism (break down of amino acids).  A cofactor or coenzyme is a molecule that interacts with an enzyme to active it.  Biotin works to bring carbon dioxide to macromolecules.  It is associated with four main enzymes in humans (3): 

Thus, biotin is vital in the metabolism of fatty acids, glucose, and amino acids.  However, alongside this, it is involved in regulating gene expression, histone modifications, and cell signalling. (4)  Biotin was first discovered in 1939 as a protective and curative factor against alopecia (hair loss) and dermatitis which suggests why we associate biotin with hair, nails, and skin. (2) Surprisingly enough, I was struggling to find enough studies that discussed the more aesthetic and cosmetology benefits of biotin.  Many actually look at biotin in the context of multiple sclerosis, breast cancer, and embryological development. Some studies illustrate very compelling results so I recommend researching the clinical benefits of biotin if you're curious. 

Biotin is usually found bound to proteins and our body breaks this down during digestion so we end up with biocytin and biotin-oligopeptides.  Finally, biotinidase (anything ending with '-ase' is an enzyme) will further catalyse the reaction to form biotin in the intestinal lumen.  Biotin is predominantly stored in the liver of animals and humans.  Thus, biotin rich foods include animal liver, egg yolk, dairy products, salmon, avacados, nuts and seeds, and sweet potatoes for example. (5) (6) It is vital that I stress that our body naturally synthesises biotin in the gut by our microbiota (naturally occurring bacteria flora in our body).  (8)

The Studies

Biotin has been given at pharmacological doses of around 20mg/day in order to reduce skin rashes, brittle nails, and various forms of hair loss. (6)  This study conducted by Floersheim in 1989 demonstrated that oral biotin has shown significant improvement in improving defects in the hooves of horses.  Therefore, they conducted a study in human participants to see if we can mirror the same benefit in nails. Although there were only 71 participants, which is a small sample size, an oral dose of 2.5 mg/day was given over 5.5 months (+/- 2.3 months).  At the end of the study, it was found that 91% of cases showed a definite improvement with harder and firmer nails.  (7)  Therefore, despite the small sample size, there appears to be a significant difference before and after taking biotin.  Nonetheless, it is important to consider that this study was only conducted in woman, and we do not know if there were any significant diet or lifestyle changes that could also contribute to improved nail strength.

A more recent study conducted in 2012 by Glynis et al was a double-blinded study to evaluate the effectiveness of biotin in women with 'perceived' hair thinning. This was an incredibly small trial of 15 individuals, where 5 were given a placebo (control group) and 10 were given biotin to take twice a day for 180 days.  The ages of the participants also ranged from 21-75 years old which could be an effect modifier.  The control group actually believed they had thicker hair at the end of the study compared to those who took the medicine! Nonetheless, over the course of 180 days it was found there were significant improvements (p value below 0.001) in the women's hair and skin.  (9)  On top of this, it appears this study was looking to just measure the affect of a specific medicine which included other vitamins and minerals such as vitamin C, niacin, horse tail, and fruit powder for example.  Therefore, it is hard to pin point if pure biotin, which is the common supplement many individuals take, is the reason why women have thicker hair growth and smoother skin.

Most studies, such as the one conducted by Mock et al used high-dose biotin (100 micrograms) which is not available or recommended as a supplement. (10) Individuals taking such high dosages when it is unnecessary can increase their risk of disorders of the thyroid such as hyperthyroidism. (11) In addition, many participants in the Mock study had a severe condition or metabolic disorder. (10) Nonetheless, this emphasises the need to either follow instructions and labels on supplement tins and consult a doctor before introducing anything new into your regimes. 

Fujimoto et al found promising results in a baby who had a biotin deficiency which became evident when weening off of breast feeding.  There was significant improvement after being given 1 mg/day of biotin.  However, results are going to be greatly significant if the individual does indeed have a deficiency in the vitamin.  As it is water soluble, excess is, more often than not, excreted into the urine so taking the supplement can prove extremely beneficial or show no difference in those who do not suffer a deficiency.  (12) 

A retrospective study of the effects of biotin on nail brittleness in Switzerland by Hochman et al found that there was a 25% increase in nail thickness in those that took biotin.  However, of the 35 participants, 64% of them had a difference.  Nevertheless, despite it being a very small sample size this is a positive result in terms of biotin.  (13)

All in all, those were the main studies that I can find that looked at the aesthetic benefits of using biotin (hair, skin, and nails)! The rest were very interesting as I aforementioned; analysing various clinical conditions that could have manifested due to a biotin deficiency or are currently being treated with biotin.  I do not think biotin will have no affect in anyone, rather, I believe that it could show small positive changes to an individual's appearance.  On top of that, I cannot reinforce the importance of ensuring you follow the label, report any differences to a healthcare provider, and even visit a doctor before including supplements into your everyday diet.  

Thank you for reading!



2.Gyorgy, Paul (December 1939). "The Curative Factor (vitamin H) for Egg White Injury, with Particular Reference to Its Presence in Different Foodstuffs and in Yeast". Journal of Biological Chemistry131: 733–744.
4.Zempleni J, Wijeratne SSK, Kuroishi T. Biotin. In: Erdman JW, Macdonald IA, Zeisel SH, eds. Present Knowledge in Nutrition. 10th ed. Washington, DC: Wiley-Blackwell; 2012:359-74.

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