Estradiol (E2)

Low levels may cause abnormal periods or infertility. Normal levels for estradiol in premenopausal women are about 15 to 350 picograms per milliliter (pg/mL), although these amounts vary widely through 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. There can also be lifestyle causes, including 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 toxic. 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, treatment with estradiol may help alleviate some of the uncomfortable symptoms of perimenopause and menopause.

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 normal 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 may need to be added to a treatment plan to reverse 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.