Anastrozole belongs to the aromatase inhibitor group . It is used to reduce estrogen levels in the body , is one of the best active ingredients to reduce the aromatization of steroids , thus suppresses the formation of gynecomastia and water retention much better than Tamoxifen or Proviron . One tablet per day (1 mg) may, after 7 days exposure to suppress estrogen up to 80% . Increases levels of testosterone own ( 1 mg daily after 7 days can increase testosterone levels by 55 % ) . The side effects include thinning hair , hot flushes , acne and also loss of appetite . Anastrozole alone has little effect on cholesterol levels , but its combination with testosterone quite strongly inhibits HDL ( good ) cholesterol , thus also reduces the immunity of the body with prolonged use . It is hepatotoxic to the liver.