Research confirms that damiana is a potent aromatase inhibitor, due primarily to the active ingredients pinocembrin and acacetin.
DIM (diindolynmethane) has a positive influence on estrogen metabolism. DIM works in the body to convert the problematic form of estrogen into a non-problematic form.
In the body, estrogen is broken down into metabolites. The three main metabolites are 2-hydroxyestrone, 4-hydroxyestrone, and 16-hydroxyestrone. These metabolites can have stronger or weaker estrogenic activity. The 2-hydroxyestrone has the weakest estrogenic activity. DIM helps to convert more estrogen into mainly the weaker form of 2-hydroxyestrone.
Iodine also helps to have a more conveniente balance between the different types of estrogens.
Reference:
Anti-aromatase activity of the constituents from damiana (Turnera diffusa). Journal of Ethnopharmacology 120:387–393, 2008.
Zhao, J., et al. Phytochemical investigation of Turnera diffusa. J Nat Prod 70(2):289-92, 2007.