Testosterone Cypionate 2500mg/10ml vial Testosterone cypionate is an injectable oil which contains testosterone with the cypionate ester attached to the testosterone molecule. The ester denotes the release pattern of the test after it is injected into the body. This particular ester gives the testosterone an active life of 15-16 days, although blood levels of this drug fall sharply five days post-administration, testosterone levels are still above baseline after a week. Stable blood levels can be achieved with once per week injections. Athletes often administer the drug twice weekly or every three to five days days. On a funny side note, many steroid users believe that test cyp is more or less powerful than the other popular injectable testosterone enanthate. The truth is, they are almost identical in release patterns, so there is virtually no difference between the two. However there has been speculation that Cyp had more "kick" than Enanthate.