What are the causes of hormone imbalance in teens?

Ovaries. Depends what type of hormone imbalance you are talking about. Often times the ovaries don't make teheproper amounts of estrogen and or progesterone, so teens can commonly have irregular periods, you can do hormone blood tests and if nothing is out of the ordinary( like low thyroid, etc. ) the teen can be cycled on low dose birth control pills to regulate the cycles.