As a dietary supplement, I3C provides key nutritional support for liver detoxification. It also plays an important role in supporting female reproductive health. The majority of ingested I3C is absorbed in the small intestine as diindolylmethane (DIM), which is thought to be the primary contributor to I3C's beneficial properties. DIM has been shown to selectively bind to estrogen receptors and may act as an estrogen antagonist at physiological concentration. In the liver, I3C promotes the metabolism of estrogen and increases the ratio of 2-hydroxy estrogen to 16-hydroxy estrogen. The 2-hydroxy estrogens, less active than the 16-hydroxy estrogens, generally are eliminated more rapidly from the body. One prospective study found postmenopausal women with the most favorable urinary 2:16-hydroxyestrone ratio were most likely to maintain good female health.