Vitamin B7 (biotin)

Vitamin B7, also known as biotin or vitamin H, is a water-soluble vitamin classified as a B-complex vitamin. Biotin can only be synthesized by bacteria, molds, yeasts, algae, and by certain plant species. In humans, bacteria in the intestine can make biotin or it can be obtained from exogenous sources (food or dietary supplements).

Vitamin B7 has vital metabolic functions. Your body needs biotin to metabolize carbohydrates, fats and amino acids, the building blocks of protein. It is often recommended for strengthening hair and nails, and it’s found in many cosmetic products for hair and skin.

Without biotin as a co-factor, many enzymes do not work properly, and serious complications can occur, including varied diseases of the skin, intestinal tract, and nervous system. Biotin is also important for normal embryonic growth, making it a critical nutrient during pregnancy.

Biotin (vitamin B7) deficiency

Biotin deficiency is rare.

Daily requirements are relatively small, food sources of biotin are abundant, and the body efficiently recycles much of the biotin it has already used. There isn’t a good laboratory test for detecting biotin deficiency, so this condition is usually identified by its symptoms.

  • Neurologic symptoms in adults have included depression, lethargy, hallucinations, numbness and tingling of the extremities,ataxia, and seizures.
  • The characteristic facial rash, together with unusual facial fat distribution, has been termed the “biotin deficient facies” by some investigators.
  • Skin issues include: seborrheic dermatitis, dry skin, brittle hair/hair loss.

Long term use of certain anti-seizure medications, prolonged oral antibiotic use, intestinal malabsorption, intravenous feeding, and eating raw egg whites on a regular basis can lead to biotin deficiency.

Sportists and people that are more physically active need more of this vitamin because it is spended in lactic acid metabolism. Lactic acid is formed after physical activity.

Food source of vitamin B7

Biotin can be found in brewer’s yeast; cooked eggs, especially egg yolk; sardines; nuts (almonds, peanuts, pecans, walnuts) and nut butters; soybeans; other legumes (beans, blackeye peas); whole grains; cauliflower; bananas; and mushrooms.

Some Food Sources of Biotin 
Food Serving Biotin (μg)
Yeast 1 packet (7 grams) 1.4-14
Bread, whole-wheat 1 slice 0.02-6
Egg, cooked 1 large 13-25
Cheese, cheddar 1 ounce 0.4-2
Liver, cooked 3 ounces* 27-35
Pork, cooked 3 ounces* 2-4
Salmon, cooked 3 ounces* 4-5
Avocado 1 whole 2-6
Raspberries 1 cup 0.2-2
Cauliflower, raw 1 cup 0.2-4
Peanuts 0.25 cup 26
Tomatoes 1 cup 7.2

Raw egg whites contain a protein called avidin that interferes with the body’s absorption of biotin. Cooking egg white denatures avidin, rendering it susceptible to digestion and therefore unable to prevent the absorption of dietary biotin.

Food-processing techniques can destroy biotin. Less-processed versions of the foods listed above contain more biotin.


There is no recommended dietary allowance (RDA) established for biotin. Adequate daily intakes for biotin, according to the National Academy of Sciences, are listed below.


  • Infants birth – 6 months: 5 mcg
  • Infants 7 – 12 months: 6 mcg
  • Children 1 – 3 years: 8 mcg
  • Children 4 – 8 years: 12 mcg
  • Children 9 – 13 years: 20 mcg
  • Adolescents 14 – 18 years: 25 mcg


  • 19 years and older: 30 mcg
  • Pregnant women: 30 mcg
  • Breastfeeding women: 35 mcg

Can vitamin B7 it be harmful?

There is no information by now about side effects of taking biotin. However, consult your healthcare provider or your pharmacist before taking vitamin supplements.

As with all supplements, check with a health care provider before giving biotin to a child.




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