Estradiol cypionate , or estradiol cipionate, is a synthetic ester, specifically the 3-cyclopentylpropanoyl ester, of the natural estrogen, estradiol. It was first introduced in 1952 by Upjohn in the United States, and has been in widespread use since. Estradiol cypionate is absorbed more slowly than estradiol itself, and for that reason, it can be administered less often.Compared to other commonly used estradiol esters, via the intramuscular route, estradiol cypionate was found to have the longest duration of action with a duration of ~11 days, while estradiol benzoate and estradiol valerate were found to last for 4-5 days and 7-8 days, respectively.

How to use estradiol cypionate intramuscular.
Read the Patient Information Leaflet if available from your pharmacist before you start using thismedication and each time you get a refill. If you have any questions, ask your doctor or pharmacist.This medication is injected into a muscle as directed by your doctor, usually every 3 to 4 weeks. Thedosage is based on your medical condition and response to treatment.