Vitamin B7 is one of the 'B' vitamins in 'B-complex' and also known as Biotin. A deficiency can lead to hair loss/alopaecia. Some, (not all), of the ways of becoming deficient is eating too many egg-whites, smoking or absorption problems. Symptoms of a deficiency can be dry scaly dermatitis, brittle hair, red rashes, lethargy, depression, dry eyes, difficulty sleeping/insomnia, listlessness, brittle nails, nausea, vomiting and tingling in the arms and legs. Biotin also supports they thyroid and adrenal glands.
Some people take Vitamin B7 to ensure a strong and healthy head of hair, but no 'B' vitamin should be taken in isolation, so 'B' complex is the ideal way of ensuring a 'B7' intake. Also, ensure appropriate minerals are included if taking a B-complex supplement. Organ meats and egg yolks are a good source as well as berries/fruits, nuts, halibut, salmon, onions, cucumber, avocado, mushrooms, carrots and cauliflower. However, always check your vitamin/mineral status first, before self-prescribing supplements.