It is important to note, there are two progesterones, one made by the body and one that is molecularly altered and patentable.
It is a common practice for health care professionals to say “progesterone” when referring to the synthetic “progestin”.
This is an important distinction, as “progestins” have a litany of side-effects. Conversely, “biologically identical progesterone” has a 40+ year history of safe, effective use, when administered in a safe cream formula.