Xenoestrogen
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
Transgender hormone therapy (male-to-female)
There are two types of progestogens: progesterone, which is the natural and bioidentical hormone in the body; and progestins, which are synthetic progestogens. There are dozens of clinically used progestins. Certain progestins, namely cyproterone acetate and medroxyprogesterone acetate and as described previously, are used at high doses as functional antiandrogens due to their antigonadotropic effects to help suppress testosterone levels in transgender women. Aside from the specific use of testosterone suppression however, there are no other indications of progestogens in transgender women at present. In relation to this, the use of progestogens in transgender women is controversial, and they are not otherwise routinely prescribed or recommended. Besides progesterone, cyproterone acetate, and medroxyprogesterone acetate, other progestogens that have been reported to have been used in transgender women include hydroxyprogesterone caproate, dydrogesterone, and norethisterone acetate. Progestins in general largely have the same progestogenic effects however, and in theory, any progestin could be used in transgender women.