Estradiol (E2)

Low levels may cause abnormal periods or infertility in menstruating women. Typical levels for estradiol in premenopausal women are about 15 to 350 picograms per milliliter (pg/mL), although these range widely throughout the menstrual cycle. The causes of low E2 levels can be genetic, autoimmune, toxic (due to chemotherapy or radiation therapy), or related to diseases of the ovaries, pituitary gland, or hypothalamus. Lifestyle causes of low estrogen levels include malnutrition, over-exercise, severe physical or emotional stress, and heavy drug or alcohol use.

Low estradiol levels can delay the development of female body characteristics and menstruation. In these cases, causes are generally genetic, autoimmune, or possibly due to chemotherapy or radiation. Estradiol may stimulate puberty in girls who are not developing naturally.

Postmenopausal women generally have less than 10pg/ml of estradiol. Although these low levels are the typical result of ovaries ceasing to function with age,  estradiol therapy may help alleviate some of the uncomfortable symptoms of perimenopause and menopause such as hot flashes, night sweats, or vaginal dryness.

Although testosterone is the primary male sex hormone, estradiol is also essential for healthy sex drive, erectile function, and sperm production. Since the estrogen men have is converted from testosterone through an enzymatic process, men with low testosterone levels also tend to have low estrogen levels. The average range of estradiol in adult males is 10-40 pg/mL. If a patient’s levels continue to be low even with testosterone therapy, estradiol therapy may address symptoms such as exhaustion, reduced sex drive, shrinking muscle mass, and osteoporosis. Persistent low estradiol levels in men may have the same causes as in women — genetic, autoimmune disorders, toxicity, malnutrition, rapid weight loss, or conditions that affect the sexual organs, pituitary gland, or hypothalamus.