The risk of hepatotoxicity and death associated with CPA treatment is reportedly the reason that CPA has not been approved by the FDA for use in the United States.  Patients being treated with high-dose CPA should be closely monitored with liver function tests .  The risk is dose-dependent, and the low doses of CPA used in birth control pills (2 mg) have been said to represent a non-significant risk.  However, a German woman who had been taking Diane-35 (containing 2 mg/day CPA) for contraception for 14 years died of liver cancer, and this led to a safety review by drug regulators and the eventual restriction of CPA throughout Europe for the indication of acne treatment in women. 
Testosterone Propionate Many consider propionate to be the mildest testosterone ester, and the preferred form for the dieting/cutting phases of training. Some will go so far as to say that propionate will harden the physique, while giving the user less water and fat retention than one typically expects to see with a testosterone.
During a typical cycle one will see action that is consistent with a testosterone. Users sensitive to gynecomastia and water retention may therefore need to add an anti-estrogen like Arimidex, Femara or Aromasin. Those particularly troubled by gynecomastia may find that a combination of Nolvadex and Proviron works especially well at preventing/halting this occurrence.