Vitamin B7, also known as Biotin, vitamin H or vitamin B8, is a water-soluble vitamin, required by all organisms. There are eight different forms of biotin, but only one of them, D-biotin, occurs naturally and has full vitamin activity. Biotin can only be synthesized by bacteria, molds, yeasts, algae, and by certain plant species. Biotin (vitamin B7) contributes to normal macronutrient metabolism, normal energy yielding metabolism, the maintenance of normal skin and mucous membranes, the normal function of the nervous system, the maintenance of normal hair and normal psychological functions. Only little is known regarding the amount of dietary biotin required to promote optimal health or prevent chronic disease. As vitamin B7 requirement cannot be accurately estimated, in 2014, the European Food Safety Authority (EFSA) recommended the adequate intake (AI) of biotin for adults and pregnant women should be set at 40 mcg per day – adding that for lactating women an additional 5 mcg/day over and above the AI for adults is proposed. Based on observed intakes in the EU, for infants over six months an AI of 6 mcg/day was proposed, while the AIs for children aged between one and three and between four to ten years were set at 20 and 25 mcg per day, respectively. For adolescents the figure was set at 35 mcg/day. Symptoms of vitamin B7 deficiency include fungal infection, seborrheic dermatitis and/or a red rash, brittle hair or hair loss, anemia, birth defects, muscle pain, mild depression, lethargy, hallucination, and anorexia. Vitamin B7 is a water-soluble vitamin, which means that any excess is excreted in the urine and feces. Symptoms of vitamin B7 overdose include an increased urge to urinate, abnormal sweating frequency; and rapid nail and hair growth.