Estrogen comes in 3 forms – Estrone (E1), Estradiol (E2), and Estriol (E3). Estradiol is the form produced in greatest abundance in the premenopausal years, and estriol, which is much less potent, is primarily the estrogen of the menopausal woman. Estradiol is produced more abundantly in the ovaries, especially in response to follicle stimulating hormone from the pituitary, serving to ripen ovarian follicles in preparation for ovulation. A significant amount of estrogen is also produced in fatty tissue. Estrogen levels can range from 400-700 in a premenopausal woman at around cycle day 12 of her cycle, to nearly zero after menopause. At age 60 an average unsupplemented woman will have lower estrogen levels than a similarly aged man.
Physiologic effects of estrogen include maintenance of uterine and breast tissue, vaginal mucosal thickness and lubrication, health of the bladder and urethra, libido, and sexual function. The presence of estrogen is associated with more favorable cholesterol profiles, blood vessel elasticity, lower inflammation in the lining of the blood vessel walls, and the inhibition of the development and progression of atherosclerosis. Healthy estrogen levels contribute to a healthy immune system, improve the function of the brain, and lower the risk of dementia, colon cancer, and macular degeneration. Healthy estrogen levels correlate with lower levels of fat in the mid-section, as well as better insulin sensitivity, increased blood sugar stability, and lower glycation. Other studies have shown the correlation between estrogen levels and quality of sleep, retention of skin thickness and elasticity. Estrogen replacement has been shown to improve mood scores in depressed subjects. The influence of estrogen on retention of bone mineral density is well-described.
Symptoms of low estrogen in women include fatigue, depression, poor sex drive, poor memory, hot flashes, night sweats, irregular or excessively heavy menstrual periods, vaginal itching or dryness, recurrent bladder infections, and an increase in muscle and joint aches and pains.
The relief of acute symptoms is the primary motivating factor for most women seeking hormone replacement therapy. While the acute symptoms of menopause typically diminish even in unsupplemented women (on average, about four years after the beginning of menopause), the rationale for continued therapy is based on the physiologic benefits of corrective hormone therapy. Certain lifestyle habits will intensify the symptoms of estrogen deficiency, including poor nutrition, excess body weight, cigarette smoking, lack of appropriate exercise, depression and anxiety, symptoms can be more severe if you become menopausal at a younger age or if your mother had more severe symptoms.
Estrogen is optimally replaced through the skin, by using a compounded cream or gel, or a patch. It should be balanced by co-administration of bio identical progesterone. Dose of estrogen is best adjusted through a combination of symptoms and blood test results.