Biotin (Vitamin B7) Sources, Health Benefits And Dosage

Reviewed by Dr. Liji Thomas, MD

Vitamin B7, more commonly known as biotin, is a water-soluble vitamin that is vital for the body’s metabolism and functioning. It is an essential component of a number of enzymes responsible for several crucial metabolic pathways in the human body, including the metabolism of fats and carbohydrates, as well as amino acids involved in protein synthesis.

Biotin is known to promote cell growth and is often a component of dietary supplements used for strengthening hair and nails, as well as those marketed for skin care.

Sources of Biotin

Vitamin B7 is found in a number of foods, though in small amounts. This includes walnuts, peanuts, cereals, milk, and egg yolks. Other foods that contain this vitamin are whole meal bread, salmon, pork, sardines, mushroom and cauliflower. Fruits that contain biotin include avocados, bananas and raspberries. In general, a healthy varied diet provides the body with sufficient amounts of biotin.

Foods rich in Biotin (vitamin B7). Foods as liver, eggs yolk, yeast, cheese, sardines, soybeans, milk, cauliflower, green beans, mushrooms, peanuts, walnuts and almonds. Image Credit: By Evan Lorne / Shutterstock

Health Benefits

Biotin is essential for the body’s metabolism. It acts as a coenzyme in a number of metabolic pathways involving fatty acids and essential amino acids, as well as in gluconeogenesis – the synthesis of glucose from non-carbohydrates. Although biotin deficiency is rare, some groups of people may be more susceptible to it, such as patients suffering from Crohn’s disease. Biotin deficiency symptoms include hair loss, skin issues including rash, an appearance of cracking in the corners of the mouth, dryness of the eyes and appetite loss. Vitamin B7 promotes appropriate function of the nervous system and is essential for liver metabolism as well.

Biotin is commonly advised as a dietary supplement for strengthening hair and nails, as well as in skin care. It is suggested that biotin aids cell growth and the maintenance of mucous membranes. Although biotin may be present in certain cosmetics, it is important to remember that it cannot actually be absorbed through skin, hair or nails.

Vitamin B7 can aid in caring for thinning hair and brittle nails, especially in those suffering from biotin deficiency. However, research so far has shown no conclusive results to back up the claim that biotin is directly related to the improvement of skin and nail condition or in increased hair growth.

Some evidence has shown that those suffering from diabetes may be susceptible to biotin deficiency. Since biotin is an important factor in the synthesis of glucose, it may help maintain an appropriate blood sugar level in patients suffering from type 2 diabetes.

Dosage

As a water-soluble vitamin, biotin is not stored in the body, instead being secreted through urine, so it must be provided in our daily diet. Some amount of vitamin B7 can also be synthesized by the bacteria living in the gut. However, since biotin deficiency is rare and the amounts needed by the body are small, many countries do not actually provide a recommended daily intake of biotin. The daily amounts suggested by the United States Food and Nutrition Board are 6 micrograms for an infant up to the age of 6 months, 30 micrograms for adults of 19 years and older and 35 micrograms in the case of breastfeeding women. Studies have shown that people consume on average 36 micrograms of biotin daily, meeting the average intake recommended above. Different amounts may be recommended to treat vitamin B7 deficiency and will be advised by a proper health professional.

According to the Mayo Clinic, a daily intake of biotin of up to 10 milligrams has no adverse effects to the body. Moreover, so far no research has shown the possibility of overdosing on vitamin B7. Since it is water-soluble, excess amounts are not stored in the body and are instead flushed out through the urine.

Sources

• Shari R. Lipner. (2018) Rethinking biotin therapy for hair, nail, and skin disorders. Journal of the American Academy of Dermatology 78:6, pages 1236-1238.
• Shari R. Lipner & Richard K. Scher (2018) Biotin for the treatment of nail disease: what is the evidence?, Journal of Dermatological Treatment, 29:4, 411-414, DOI: 10.1080/09546634.2017.1395799
• Pacheco-Alvarez, Diana et al. Biotin in Metabolism and Its Relationship to Human Disease. Archives of Medical Research , Volume 33 , Issue 5 , 439 – 447, https://www.arcmedres.com/article/S0188-4409(02)00399-5/ppt
• Mayo Clinic: Biotin (Oral Route), https://www.mayoclinic.org/drugs-supplements/biotin-oral-route/description/drg-20062359

Further Reading

• All Vitamin B7 Content