Some iS Clinical products contain soy isoflavones and hydrolyzed soy protein. Soy may be considered a xeno-estrogen since it is a phytoestrogen (plant source of selective estrogen receptor activity). The highest source of estrogen stimulation in our society’s children is thought to be childhood obesity. Most xeno-estrogens and phytoestrogens come from ingested sources in foods. iS Clinical products, except possibly for the Prodigy Peels, are not absorbed through the deeper skin layers and have no systemic effect.