Contraception. 1980 Apr;21(4):415-24.
"Pharmacokinetic properties of 3 natural estradiol esters, (estradiol cypionate, valerate, and benzoate), were assessed by assaying daily plasma levels of estradiol and estrone in groups of 10, 9, and 10 subjects, respectively, before and during 3 weeks of intramuscular administration"
"Estradiol and estrone levels both reached peak levels about 4 days after the injection of the cypionate ester and about 2 days after administration of the valerate and benzoate esters. Estrogens were elevated for the shortest time (4-5 days) with the benzoate ester, which was followed by the valerate (7-8) and the cypionate (about 11 days). After 2 weeks, no subjects showed elevated estradiol or estrone levels."
Most use valerate (including myself), a few use cypionate and rarely, benzoate.
I personally think there is no point in measuring levels as they fluctuate so much. I inject every 5 days and my levels went from 2,500 pg/ml to 1,500 pg/ml in just TWO DAYS.
There is no such thing as an ideal level, no way to establish it as there is so much cyclicity in natal females and so much variation in sensitivity in human beings to levels. Levels also do not appear to be a fair gauge of health risk as very high levels in natal women and men have shown to be quite safe as long as it is estradiol and usually, taken non-orally or produced endogenously.
