Made in the liver, SHBG is a protein that works to regulate the balance of sex hormones in the body. When SHBG binds itself to estrogen, testosterone, or DHT, it takes the hormone molecule in question out of commission in a process similar to that of antioxidants fastening themselves to free radicals. Women diagnosed with Polycystic Ovary Syndrome (PCOS), which is associated with increased levels of testosterone, often have decreased amounts of SHBG, while it is believed that postmenopausal women with higher levels of SHBG often have a lower risk of breast cancer.