Biotin (also known as vitamin B₇ or vitamin H) is a water-soluble vitamin that is necessary for the human body to function properly. Because only a small amount of biotin is needed, a biotin deficiency is quite rare. Most people obtain all the biotin they need through dietary means, and the body also produces biotin naturally. However, some people who have certain medical conditions or who are taking certain medications may have low levels of biotin, and supplementation is necessary.