Estrogen is the primary female sex hormone. It is responsible for the development and regulation of the Female Reproductive System, and secondary sex characteristics.

Estrogen may also be classified as any substance, natural or synthetic, that acts similar to the effect of the natural hormone. It is synthesized in all vertebrates and some insects.

Estrogen is a group of compounds that are synthesized and referred to as “steroids“. Estrogen can be found in both males and females. The levels are much higher in women of childbearing age.

Estrogen a large importance in the “estrous cycle” – which is a physiologic change that occurs during the Reproductive and menstrual cycle.

Estrogen is the primary female sex hormone but is also used with ProgesteroneLH, and FSH.

Three main types of estrogen that are found in nature

1.)  Estradiol
2.)  Estriol
3.)  Estrone
4.)  Estetrol is only produced during pregnancy

Cholesterol is the main ingredient in estrogen formation but Testosterone is also involved.


Estrogen is primarily produced within the Ovary. It is specifically found in the follicles, corpus luteum and the Placental as well.

Much smaller amounts can be produced in the Breasts, Adrenal Gland, and the Liver. FSH and LH cause the reaction that produces Estrogen in the ovaries.



–  Helps regulate menstrual cycles
–  Promote the development of Breasts
–  Causes thickening of Endomentrium


–  Help in sperm development
–  Arguments have been made that it is necessary to maintain a healthy libido


–  Promotes formation of sex characteristics
–  Accelerate Metabolism
–  Fat storage
–  Helps with Uterine Growth
–  Helps with Endometrial Growth
–  Thickens Vaginal walls.
–  Decreases resorption of bone

Hormone Replacement Therapy

Estrogen for use as a medication can be prescribed for those who are postmenopausal. Estrogen and other hormones are given to prevent osteoporosis.

Estrogen treatment-related symptoms:

–  Hot flashes
–  Dizziness
–  Fatigue
–  Sweating
–  Vaginal dryness
–  others

Important Things to Understand

*** – Some risks may increase with Hormone Replacement Therapy.

And research is currently in progress to determine the overall risk vs. benefit for this treatment plan. Estrogen itself may be an important player in breast cancer. Many breast cancers are “hormone-sensitive

This means, that in order for these cancers to survive and even become larger, is directly controlled by the level of estrogen in the body.

Treatment may, therefore, be the decrease or suppression of this hormone

Typically seen in 75-80% of breast cancers

Estrogen is also used directly in medication for contraception and hormone replacement in some women.