Progesterone is produced in the female body in the ovaries. Progesterone production is high during the luteal phase (second portion) of the menstrual cycle and low during the follicular phase (first portion), as well as being low before puberty and after menopause.
Supplemental sources of progesterone are available in oral and cream forms, as well as lozenges, suppositories, and injectable forms. "Natural" progesterone refers to the molecule that is identical in chemical structure to the progesterone produced in the body, even if the molecule is synthesized in a laboratory.
Progestins are found in oral contraceptive pills and are used in conventional hormone replacement therapy.
Wild yam contains precursors to progesterone (such as diosgenin) that can be converted through a chemical process in the laboratory into progesterone--the exact same molecule made in the human body. However, contrary to popular claims, the diosgenin in wild yams cannot be converted into progesterone in the body.21, 22 Women who require progesterone should consult their physician and not rely on wild yam or other herbs.
Pregnenolone, another hormone produced by the body, is converted by the body into progesterone. However, it is not clear what effect supplementing with pregnenolone will have on progesterone production in the body.