Estradiol

ESTRADIOL (E2)

Estradiol is one of the main estrogens (female sex hormones). Estradiol is a steroid hormone that is synthesized in the ovaries, the outermost layer of the adrenal glands, and to a lesser extent in the testicles. Adipose tissue also produces small amounts of estradiol. Estradiol is also produced by the placenta during pregnancy. In women, estradiol secretion is regulated by the follicle-stimulating hormone (FSH) produced in the adrenal gland. In men, estradiol is also created when testosterone is converted into estradiol by the aromatase enzyme.

Estradiol metabolizes mostly into estriol (E3) after being conjugated in the liver and secreted into urine, bile, and feces. Estradiol binds to proteins (SHBG and albumin) in the blood. Estrogen affects various target tissues through estrogen receptors. Estradiol is a female sex hormone, which is required for reproduction and sexual activity. It is also crucial for bone health, cardiovascular and circulatory system, immune system, sugar metabolism, and nervous system. The estradiol levels of a woman vary depending on the age, menstrual cycle phase and reproductive stage (breastfeeding, pregnancy, etc.). In men, the estradiol levels are low and should be below the reference range.

Various environmental factors may increase the levels of estradiol in the body. These include xenoestrogens such as microplastics, BPA and phthalates as well as certain phytoestrogens in food, food additives, hormone-treated agricultural products, alcohol, and water contaminated by contraceptive pills. These so-called endocrine disruptors may form predisposing factors for cancers, diabetes, infertility, and metabolic syndrome as well as various developmental disorders.
Significantly higher estradiol levels occur in association with hyperthyroidism, liver cirrhosis, and adrenal or ovarian tumors (in women). Continuous stress and excessive cortisol production may also increase estradiol levels. Obesity appears to increase estradiol levels as well – adipose tissue is known to store and produce estrogen hormones. Low levels occur in women with pituitary failure, Turner's syndrome, anorexia, PCOS or hypogonadism. Low levels may also occur in association with extreme endurance sports.

Our living environment full of modern chemicals, medicines and other environmental toxins, as well as food additives, has brought on a significant rise in estrogen levels in both women and men. In some cases, the excessive amount of estrogen is referred to as “estrogen dominance” due to its dominating role in the balance of sex hormones.