I have always taken Test E. Cyp and Enanthate are esters that have been attached to the 17 beta hydroxyl group of the testosterone molecule, which increase the active life span of the steroid preparation. Once a steroid is injected it will form a deposit I. The muscle tissue and slowly enter circulation. The higher the ester the more oil soluble the steroid compound d will be and the longer it will take for full dosage to be released. Esters provide various release times some want fast release others want slower release. Do what fits your wants or needs!