Suppression of testosterone levels by MGA is responsible for its effectiveness in the treatment of conditions like prostate cancer and benign prostatic hyperplasia. In one study, 120 to 160 mg/day MGA suppressed testosterone levels in men by 72%. However, a recovery or "escape" of testosterone levels, gradually returning to near-normal values, has been observed in most men after 2 to 6 months of MGA therapy, and this has limited the usefulness of the medication. The combination of a lower dosage of MGA (40–80 mg/day) and a low oral dosage of an estrogen such as estradiol (0.5–1.5 mg/day), diethylstilbestrol (0.1–0.2 mg/day) or ethinylestradiol (50 µg/day) is able to suppress testosterone levels into the castrate range in men, maintain this suppression long-term, and achieve equivalent effectiveness to high-dosage estrogen monotherapy in the treatment of prostate cancer with comparatively greatly reduced toxicity and side effects. In spite of these results however, this combination has been very rarely used to treat prostate cancer in the United States.