Biotin is a vitamin that your body needs to stay healthy and is easily obtained from a well-balanced diet. Although biotin deficiency is rare, it can develop if you have an underlying medical condition, are taking certain medications or are pregnant. As a dietary supplement, biotin is claimed to treat many conditions, including hair loss, brittle nails and skin conditions, but taking more than the recommended dosage may not be effective.
The adequate intakes for biotin are 30 micrograms for adults over 18 years and pregnant women and 35 micrograms for breastfeeding women.
What Is Biotin?
Biotin, also known as vitamin H or B7, is an essential vitamin that helps your body break down fatty acids and metabolize carbohydrates and protein for energy. You can get biotin from the food you eat, and it's also produced in your intestines. Biotin is vital for the health of your bones, skin and nails, as well as for keeping your liver and nervous system functioning properly. During pregnancy, biotin is especially important for normal fetal development.
Food Sources of Biotin
Since biotin is water soluble, you need to include foods in your daily diet that contain the vitamin. To ensure you get enough biotin, eat a variety of foods and choose from some of the following good sources of biotin:
- Meat, fish and organ meats, such as liver
- Egg yolks
- Cheese and cow's milk
- Seeds, nuts and legumes
- Certain vegetables such as cauliflower, sweet potatoes, spinach, carrots, mushrooms and broccoli
- Whole grains, including rice and wheat germ
- Some fruits such as apples, bananas and tomatoes
What Causes Biotin Deficiency?
If you're healthy, it's easy to get sufficient biotin from your diet when combined with the amount made by your body. However, certain circumstances can create a risk for a deficiency of biotin, including hereditary conditions such as:
- Biotinidase deficiency — an inherited metabolic disorder that can cause biotin deficiency. It restricts the body's ability to produce enough enzymes needed to release biotin from dietary proteins during digestion. Biotinidase deficiency usually occurs in infants within the first few months of life or in later childhood, causing an impaired immune system and susceptibility to bacterial and fungal infections, says the Linus Pauling Institute.
Other lifestyle, dietary, medical and physical conditions may also contribute to risk of biotin deficiency. Some of these include:
- Eating raw egg whites — egg whites can bind to biotin in your intestine, keeping it from being absorbed. If you ate two or more uncooked egg whites daily for several months, you could develop a biotin deficiency.
- Being pregnant, which increases your need for biotin. Biotin is important for normal embryonic growth, making it a critical nutrient during pregnancy. At least one-third of women develop a biotin deficiencies during pregnancy.
- Infant consumption of breast milk with low amounts of biotin
- Prolonged intravenous feeding without biotin supplementation
- Inflammatory bowel disease or other gastrointestinal tract disorders that impair biotin absorption
- smoking cigarettes
- Alcohol dependence or use of intravenous drugs
- Anti-seizure medications for epilepsy
- Suffering certain kinds of liver disease, such as cirrhosis
- Receiving kidney dialysis
- Being severely or chronically malnourished
- Using antibiotics
- Being diabetic
Symptoms of Biotin Deficiency
Although rare, a biotin deficiency is often characterized by "biotin-deficient facies" with a facial rash around the eyes, nose, mouth and anal area and unusual facial fat distribution. Some other symptoms of a deficiency in biotin that can have adverse health effects, include:
- Thinning hair or loss of body hair
- Skin infections, including eczema
- Brittle, splitting nails
- Neurologic symptoms such as depression, lethargy, hallucinations, numbness and tingling of the extremities
- Lack of coordination and seizures
- In infants — weak muscle tone, sluggishness and delayed development
What’s a Safe Biotin Dosage?
Although there's no recommended dietary allowance (RDA) established for biotin, the National Institutes of Health has listed the daily adequate intake (AI) for biotin daily requirements, dependent on your age:
- Infants, birth to 6 months — 5 micrograms
- Infants, 7 to 12 months — 6 micrograms
- Children, 1 to 3 years of age — 8 micrograms
- Children, 4 to 8 years of age — 12 micrograms
- Teens, 14 to 18 years of age — 25 micrograms
- Adults, 19 years and older — 30 micrograms
- Breastfeeding women — 35 micrograms
Read more: Biotin & Breast-feeding
Prescribed high therapeutic doses of biotin are often administered in amounts that exceed the recommended intake. For example, to treat biotinidase deficiency, oral supplementation with 5 to 10 milligrams of biotin daily is often prescribed.
Treatment for holocarboxylase synthetase (HCS) deficiency often requires pharmacologic doses of biotin, which can be 10 to 80 milligrams. To correct a biotin deficiency in adults and infants, the dosage might be up to 10 milligrams.
Read more: Can You Take Biotin While Pregnant?
If you have a biotin deficiency or are pregnant or breastfeeding, supplements may be beneficial and are available in many forms. Some multivitamin and multimineral supplements, as well as some B-complex supplements contain biotin. Oral supplements containing biotin come in tablet, capsule, liquid and powder form. Standard preparations are available in dosages of 250, 300, 500 and 1,000 (extended release) micrograms.
Be sure to consult with your doctor before taking biotin supplements as they can interfere with some lab tests and give false readings, such as with thyroid hormones. Otherwise, there's very little risk associated with taking biotin supplements because they're not associated with toxicity or overdose.
For skin health, MedlinePlus says that biotin, used in a product containing 0.0001 to 0.6 percent biotin, is likely safe. Topical applications in liquid and shampoo forms, to prevent hair loss, contain dosages ranging from 0.002 milliliter per 1 milliliter to .06 milliliters per 100 milliliters.
Some of the alternate names for biotin that may appear on supplement labels are:
- Coenzyme R
- Vitamin B7
- Vitamin H
- W Factor
Read more: Signs of Too Much Biotin in Your System
Biotin for Hair Growth
Biotin is often promoted to help with hair loss or to improve the health of your hair, skin and nails. But evidence from most scientific research does not support biotin as effective for treating hair loss or nail and skin conditions, except in people born with deficiencies or who have certain medical conditions. One example reported from NIH says that high doses of biotin may improve a rare hair disorder in children or skin rashes in infants deficient in biotin.
A study, published in Skin Appendage Disorders in 2017, found clinical improvement from biotin supplements in patients with an underlying medical condition causing poor hair or nail growth. Administering a biotin dosage of 2,500 or 3,000 micrograms per day improved nail strength and hardness. Researchers noted that individuals who had a biotin deficiency caused by genetic factors or diseases, such as brittle nail syndrome, may experience some positive results from biotin. However, the conclusion did not confirm that high-dose biotin supplements provide benefits to healthy individuals.
Interactions and Risks
Taking high-dose biotin supplements may interfere with many different blood tests, causing false results. This may lead to missed or incorrect diagnoses. The low biotin dosage in most multivitamins are not likely to interfere with blood tests, but consult with your doctor to be sure.
Before taking biotin, talk to your health care provider, because many drugs may interact with biotin, including prescription and over-the-counter medicines, vitamins and herbal products. Taking biotin and pantothenic acid (vitamin B5) together or alpha-lipoic acid and biotin together can cause a reduction of your body's absorption ability.
Certain prescription medicines can lower your blood level of biotin, and may require an adjustment to your dosage. If you take any medications that are changed by the liver, biotin may lessen their effectiveness, according to MedlinePlus.
- National Institutes of Health: Biotin
- Medical News Today: Why Do We Need Biotin?
- MedlinePlus: Biotin
- NIH Genetics Home Reference: Biotinidase Deficiency
- Linus Pauling Institute: Biotin
- NIH GARD: Holocarboxylase Synthetase Deficiency
- Medical News Today: Does Biotin for Hair Growth Work?
- DrugBank: Biotin
- Toxnet: Biotin
- Skin Appendage Disorders: A Review of the Use of Biotin for Hair Loss
- AACC: The Unintended Consequences of Biotin Supplementation: Spurious Immunoassay Results Lead to Misdiagnoses
- Drugs.com: Biotin