I consider cyp usually as a ester that is injected once a week. And I consider test E something injected twice per week. That is just what I have noticed the majority of people doing. So I figure injecting test E twice a week gives more stable blood levels. And test C once a week might not be as stable of blood levels but it seems that's what most Doctors give patients still is test cyp. If im wrong some one correct me please lol I am still just here to expand my knowledge Im not a die hard believer in what I have stated. It just seems like what I have noticed.