Estradiol is a member of the class of steroid hormones known as estrogens. While it is primarily a female sex hormone produced by the ovaries, it plays a role in the male body also.
In early reproductive years in females, estradiol is the primary controller that develops and maintains female sex characteristics during puberty, such as breast development, changing in body shape etc.
In males, estradiol maintains erectile function & labido and assists in the production of sperm.
Outside of puberty, high estradiol levels in females may indicate tumors in the breast, hyperthyroidism and even cirrhosis. Low levels can indicate the onset of menopause, and disorders such as polycystic ovarian syndrome. Estrogen production is also depleted once estradiol levels are sub-optimal. Estradiol has been linked to the activation of breast cancer oncogenes.
In males, gynecomastia can occur from high levels of estradiol while sperm production can also be affected. Low levels of Estradiol can have an effect on sperm quality and motility.