was ist östrogen — what are common causes?

Estrogen is a primary female sex hormone produced mainly in the ovaries, but also in adipose tissue and the adrenal cortex. It regulates the menstrual cycle, fertility, and influences bone metabolism, cardiovascular health, and mood. Common causes of estrogen excess include obesity (adipose tissue produces estrogen), certain tumors (e.g., ovarian tumors), or hormone replacement therapy. Estrogen deficiency typically occurs during menopause, but can also result from stress, excessive exercise, eating disorders, or hypothalamic dysfunction. Environmental chemicals (xenoestrogens) from plastics or pesticides may also disrupt hormonal balance. The provided context contains no specific data on estrogen; this answer is based on general medical knowledge. Evidence is therefore rated as mechanistic, not supported by the given sources.