Epitestosterone, aut isotestosterone, also known as 17α-testosterone aut ut androst-4-en-17α-ol-3-one, est endogenous steroid et epimer of androgeni sex hormone testosterone. Imbecillus auctor contra androgenium est (AR) et potentior 5α-reductase inhibitor.
Structually, epitestosterone a testosterone tantum differt in configuratione ad carbonem hydroxytryon, C17. Epitestosterone is believed to form in a similar way to testosterone; a 1993 study found that around 50% of epitestosterone production in human males can be ascribed to the testis, although the exact pathway of its formation is still the subject of research. It has been shown to accumulate in mammary cyst fluid and in the prostate.Epitestosterone levels are typically highest in young males; sed, by adulthood, most healthy males exhibit a testosterone to epitestosterone ratio (T/E ratio) of about 1:1
