Biotin, or vitamin B7, is a water-soluble vitamin that is required by the body to drive crucial cellular functions. It is not synthesized by body cells so a healthy, balanced diet is required to get vitamin B7. It can only be synthesized by certain bacteria, mould, algae and fungi. The healthy bacteria in the gut also produce biotin, but this is not enough to drive vital cellular processes and external sources are required. (Read more: Probiotics).

The central function of biotin is that it acts as a cofactor in the breakdown of fats, carbohydrates and proteins. This means that it binds with other molecules that catalyze the breakdown of food to drive metabolism. Biotin is also involved in the regulation of cell signalling, gene regulation, and histone modification. It is also required for the normal functioning of the nervous system, the maintenance of normal skin and mucous membranes, maintenance of hair as well as normal psychological functions. 

Biotin deficiency is rare in healthy people who eat balanced diets. The vitamin is required in trace amounts and is easily acquired through nutritional intake. There is not enough evidence to suggest RDA (recommended dietary allowance) but adequate intake (AI) is 30 µg (micrograms) daily for adults, and 35 µg for lactating mothers. (A microgram is one-thousandth of a milligram.)

Most biotin found in food is bound to proteins, but it does exist in free form as well. Egg yolk, liver, and yeast are common sources of biotin. Supplements are also available and may be prescribed for certain disorders.

Biotin has become popular since a deficiency will lead to hair loss (alopecia) and skin or nail problems. However, there is no clear evidence to suggest that biotin supplements have any therapeutic action against these issues. There is preliminary evidence suggesting that biotin may help those with diabetes mellitus and multiple sclerosis (MS) but more research needs to be conducted.

Studies so far have found no toxic effects of taking high doses of biotin. Since the vitamin is water-soluble, it is usually removed on urination without disrupting natural body processes. 

It has been reported that biotin supplements can affect blood test readings, so you may need to stop taking supplements before a diagnostic test. Certain drugs such as anticonvulsants are known to interact with biotin and lower its effectiveness as well. Those who consume raw eggs also run the risk of lowering their biotin levels as a protein in raw egg whites called avidin binds with the vitamin and disrupts its absorption. 

Overall, most people are able to satisfy their bodily requirements for biotin without the need for supplements. The cosmetic benefits seem to be exaggerated and more studies need to be conducted to better understand any links.

(You may also be interested in Skin disorders and diseases, and Nail fungus)

  1. Biotin deficiency
  2. Vitamin B7 rich foods
  3. Vitamin B7 supplements: who should take them and why
  4. Vitamin B7 drug interactions

As mentioned above, biotin deficiency is rare. Adequate intake for adults is 30µg and 35µg for lactating women. It is less for those under 18. Blood tests that show reduced propionyl-CoA carboxylase (PCC) and reduced urinary excretion of biotin are indicators of a deficiency. The following populations are at elevated risk: 

  • Those with liver diseases, since most biotin is stored in the liver.
  • Those who have an alcohol addiction. Chronic exposure to alcohol has been linked to lower biotin levels. 
  • Up to a third of pregnant women have a slight decrease in biotin because of the increased demand on their bodies.
  • Those who have had their stomach surgically removed, those who are on intravenous feeding (food tubes) long term. 
  • Those who have been taking anticonvulsant medications long term.
  • Those who consume high quantities of raw eggs. Caesar salad dressing and eggnog are common examples. 
  • Chronic smokers: Smoking increases the risk of biotin deficiency.

Biotinidase deficiency is a rare autosomal recessive disorder (a type of genetic disorder) that prevents the body from releasing excess biotin. Without treatment, the disorder can cause serious symptoms and even death. Oral biotin is given for life to those with the disorder and the outcome is generally positive. These are the signs and symptoms of a biotin deficiency: 

  • Thinning hair, or alopecia
  • Scaly skin on the face, including eyes, nose, mouth
  • Brittle nails
  • Impaired coordination 
  • Depression
  • Fatigue
  • Numbness in extremities 

More severe symptoms—mostly seen with untreated congenital disorders—include: 

  • Impaired immune system function and lower immunity 
  • Seizures
  • Optical atrophy
Multivitamin capsules
₹649  ₹995  34% OFF

There are many natural sources of biotin, including: 

Good bacteria in the gut also produce biotin but this itself is not sufficient for bodily requirements. If testing reveals that you are deficient in this vitamin, you may be advised to take a supplement. 

According to the US National Institutes of Health (NIH), there is only limited and insufficient evidence to suggest that biotin supplements improve the condition of brittle nails. There is also scant evidence to support a link to alopecia (hair loss) and rashes. A meta-analysis conducted in 2017 showed that biotin therapy did help slightly with hair and nail growth, but largely in cases with rare inherited diseases or in people with underlying pathologies. The authors concluded that for healthy people with normal biotin levels, supplementation did not help. 

(Read more: Home remedies for glowing skin)

As for the brittle nail studies, there were no placebo groups and the baseline levels of biotin were not measured. The studies were also small in size and more evidence is needed before any claims can be made.

For skin and hair growth, the vast majority of studies have been done in children, and again the evidence is thin. In terms of hair health, it was found that children with uncombable hair syndrome (a rare disorder involving the hair shaft) benefited from biotin treatment. These findings seem to underline the fact that supplementation won’t benefit those who don't have underlying conditions.

(Read more: Natural remedies for hair loss)

There is also some very limited evidence that biotin supplementation can improve the symptoms of MS (multiple sclerosis) and type 2 diabetes. MS is characterized by the progressive degeneration of myelin sheaths in the central nervous system (brain and spinal cord). Biotin plays a role in the intermediary metabolism required for myelin formation, so use was hypothesized as a potential therapy. The results of a randomized controlled trial were mildly encouraging; 13 out of 103 patients receiving daily biotin for 48 weeks achieved a sustained improvement of MS-related symptoms. Out of 51 placebo patients, no one showed any improvement.

As for diabetes, it has been shown that biotin can improve glucose utilization and there is evidence to suggest that biotin levels may be low in patients with type 2 diabetes. Studies so far have been limited and contradictory—one investigation showed that fasting blood glucose levels were lower after biotin therapy whereas another showed that biotin had no effect whatsoever on blood glucose levels. 

Biotin supplementation is the preferred treatment for congenital defects that lead to lower levels of biotin in the body. Those who are not treated can suffer serious symptoms or even death. 

All in all, the evidence for biotin therapy is solid only for clinically low levels of the vitamin. It has generated interest because of its relation to hair loss, skin rashes and brittle nails, but further research is needed to solidify these claims. 

Fortunately, even high doses of biotin do not seem to have adverse health effects. However, biotin supplements can influence blood tests and produce skewed results. This can have harmful effects if treatment is based on these flawed diagnostic results. 

It has been found that long-term use of anticonvulsant medication (used for the management of epilepsy) reduces biotin levels in the patient's body. These drugs catabolize (break down) biotin which leads to lower rates of absorption in the gut. It has been suggested in the literature that long term treatment with antibiotics can also lower biotin levels but this has not been confirmed with any studies.

Vitamin B5 may compete with biotin in cellular uptake as they both rely on human sodium-dependent multivitamin transporter (hSMVT) for absorption. However, this has not been confirmed in human studies and there is only limited evidence in rats. 

Find Naturopathy Doctor in cities

  1. Naturopathy Doctor in Noida

Medicines / Products that contain Biotin


  1. Office of Dietary Supplements [Internet]. National Institutes of Health, U.S. Department of Health and Human Services Biotin-- Fact Sheet for Health Professionals
  2. Deepa Patel, et al. A Review of the Use of Biotin for Hair Loss Skin Appendage Disord. 2017 Aug; 3(3): 166–169. PMID: 28879195
  3. Shari Lipner, et al. Biotin for the Treatment of Nail Disease: What Is the Evidence? J Dermatolog Treat . 2018 Jun;29(4):411-414. PMID: 29057689
  4. Zara Latif, et al. Aberrant Thyroid Function Tests in a Patient Taking Biotin Supplements Cureus. 2019 Aug; 11(8): e5297. PMID: 31579637
  5. Yousef Hassan, et al. Biotin and Biotinidase Deficiency Expert Rev Endocrinol Metab . 2008 Nov 1;3(6):715-724. PMID: 19727438
  6. D M Mock. Skin Manifestations of Biotin Deficiency Semin Dermatol . 1991 Dec;10(4):296-302. PMID: 1764357
  7. J Zempleni, et al. Biotin Biochemistry and Human Requirements Nutr Biochem .1999 Mar;10(3):128-38. PMID: 15539280
  8. Danni Li, et al. Association of Biotin Ingestion With Performance of Hormone and Nonhormone Assays in Healthy Adults JAMA . 2017 Sep 26;318(12):1150-1160. PMID: 28973622
  9. Hamid Said, et al. [Link] Am J Clin Nutr . 2002 Feb;75(2):179-80. PMID: 11815306
  10. Rubina Kapadia, et al. Chronic Alcohol Exposure Inhibits Biotin Uptake by Pancreatic Acinar Cells: Possible Involvement of Epigenetic Mechanisms Am J Physiol Gastrointest Liver Physiol . 2014 Nov 1;307(9):G941-9. PMID: 25214397
  11. K H Krause, et al. Impaired Biotin Status in Anticonvulsant Therapy Ann Neurol . 1982 Nov;12(5):485-6. PMID: 7181453
Read on app