Oestradiol 17-heptanoate is a sex hormone that is present in both males and females, and is the most important form of estrogen in humans. In women, it plays a key role in the development and functioning of the reproductive system, as well as in the growth of certain bones. It also governs the distribution of body fat in women and is the main hormone responsible for the fact that women are shorter than men, on average. Both the ovaries and the adrenal glands produce it.
Estradiol enanthate is an estrogen medication which is used in hormonal birth control. It is formulated in combination with dihydroxyprogesterone acetophenide (DHPA; algestone acetophenide).