Androstenedione is a weak male sex hormone that primarily serves as a precursor for the formation of testosterone and estrogen. It is produced in women in the adrenal cortex and ovaries, and in men in the testes, with the majority in men being immediately converted into testosterone.

Since androstenedione originates from both the adrenal glands and the gonads, its blood level can provide insights into the function of these organs. Elevated levels occur in hormone-producing tumors, congenital adrenal disorders, or polycystic ovary syndrome and can lead to increased body hair, acne, and menstrual irregularities in women. As a marker, androstenedione is used in conjunction with other hormone tests to clarify early signs of puberty in children, fertility issues, or possible adrenal hyperfunction.