Estradiol should not be supplemented for men.

Helps this masculine man. Low E2 is one of the most awful experiences.

Estradiol isn’t very well studied. It may be used for a few years in menopause, only in rare cases off-label, otherwise. Scientific and commercial interest seems pretty non existent. Probably because patentable synthetic derivatives historically fared worse risk-wise, than bioidentical estrogens, and the market outside of menopause issues is too small. Research on trans people, who would make interesting study subjects for hormonal matters, just got outlawed in the US.

Hormonal contraceptives typically do not contain estradiol, but ethinylestradiol and/or progestins.

I was going to note that a relatively large sample group has been taking estradiol en masse for many years, but you rightly called out that studying trans folks is now forbidden in the US. A shame, we could have offered up quite a bit of knowledge on it.

Estradiol is _extremely_ well studied, including non-HRT in AFAB/AMAB cisgender eugonadal populations

Birth control uses Ethinyl Estradiol which, despite the name, is not actually Estradiol and so does not undergo the same metabolic pathways and metabolites production

I know this because I recently had to source exogenous Estradiol for my wife after making this same mistaken assumption and being surprised at bloodwork and lack of improvement