Vitamin B7 or Vitamin H or Coenzyme R or Biotin is a water soluble vitamin. It promotes cell growth, supports adrenal functions and necessary for metabolic functions.

Daily requirement of Vitamin B7 in the body
0 to 6 months : 5 mcg
7 to 12 months : 6 mcg
1 to 3 years : 8 mcg
4 to 8 years : 12 mcg
9 to 13 years : 20 mcg
14 to 18 years : 25 mcg
Above 19 years : 30 mcg
Pregnancy / Lactating : 30 / 35 mcg

Functions of Vitamin B7 in the body
Vitamin B7 is a co-factor in metabolic functions. In the absence of Vitamin B7 various enzymes do not work properly. This leads to various diseases of the Skin and Nervous system. Vitamin B7 keeps the hair and nails healthy. It provides relief to a person with type 2 diabetes by increasing glucose tolerance and decreasing insulin resistance.

Deficiency of Vitamin B7 causes
Anemia
Fatigue
Anorexia
Dry Skin
Hair fall
Depression
Muscular Pain
Fungal Infection
Seborrheic Dermatitis

Excess of Vitamin B7 causes
Chances of excessive Vitamin B7 are rare. Vitamin B7 being water soluble is flushed out through urine or feces. However, if Vitamin B7 goes excess in the body, it causes :
Excessive Urination
Excessive Sweating
Increased Hair and Nail growth
Eosinophilic Pleuropericardial Effusion : It happens when Vitamin B7 and B5 are taken in excess.