While ''estrogen'' is often used as a general term, it actually refers to a group of the primary female sex hormones. Estrogens are produced primarily in the ovaries, the corpus luteum, and the placenta. Some estrogens are also produced in smaller amounts by other tissues such as the liver, adrenal glands, body fat, and breasts. Estrogens promote the development of female secondary sexual characteristics, such as breasts, and are involved in the menstrual cycle. In the uterus, estrogen causes the lining (endometrium) to thicken and build up each month until it is sloughed as a menstrual period.

There are three principal forms of estrogen found in the human body: estrone, estradiol, and estriol. There is also a group of compounds called phytoestrogens, generally found in food and herbs, which have been shown to have ''estrogen like'' effects in the body.

While we tend to think of estrogen's relationship to our reproductive function first, this hormone actually nourishes and protects our bodies in hundreds of ways, from our bones, to our cholesterol levels, to our skin, hair, and brains.

Estrogens Are Not All Alike

The three major estrogens in the body are all produced from androgens through enzyme action.

• Estradiol, produced from testosterone, is the most potent form of estrogen, and the one produced in the largest amounts by a woman's ovaries before menopause. Estradiol levels fall after menopause and after hysterectomy when the ovaries are removed.
• Estrone, produced from androstenedione, is the predominant estrogen in a woman's body after menopause. When ovarian function declines, the fat cells in a woman's body take over the role of synthesizing estrone. Premarin and Ogen contain estrone (Premarin also contains other estrogens derived from the urine of pregnant horses).
• Estriol is known as the ''weak'' or ''forgotten'' estrogen. Produced in large amounts by the placenta during pregnancy, estriol is also converted in small amounts by the liver. In post-menopausal women more estrone is present than estriol or estradiol. Estriol is not commercially available in the U.S.

Self-Care

Estrogen therapy is commonly prescribed for women as their natural estrogen levels decline after menopause or due to a hysterectomy when the ovaries are removed. Whether a woman chooses prescription estrogen therapy or not, self-care, including exercise and a healthy diet, is an important foundation for hormone balance. Vaginal Moisturizing Therapy and specially formulated vitamin supplements such as ProCycle^® Gold are non-prescription options that also help support a healthy hormone balance.

Prescription Therapy

Natural low-dose estrogen therapy can have many benefits for helping women maintain a healthy hormone balance during menopause and beyond. Madison Pharmacy Associates offers customized, low-dose prescriptions in a variety of dosage forms. As with all of the major hormones, baseline and follow-up testing of estrogen levels is critical for maintaining hormone levels in a therapeutic range and avoiding the side effects of underdosing or overdosing.

In the right amount, estrogen can protect against:

• Osteoporosis
• Colon cancer
• Tooth loss/decay

In the right amount, estrogen may enhance:

• Sleep
• Mood
• Mental sharpness/memory
• Sex drive
• Skin tone
• Brain chemicals like serotonin and endorphins

Cholesterol and Cardiac Health

As women grow older, their cholesterol levels normally rise. For women who have had one or more ovaries removed, cholesterol levels increase even faster. Benefits and risks of estrogen therapy in regard to cholesterol and cardiac health are still being assessed. Estrogens with or without progestins should not be used specifically for the prevention of cardiovascular disease or dementia. Estrogens with or without progestins should be prescribed at the lowest effective doses consistent with treatment goals and risks for the individual patient. Research on estrogen therapy is ongoing and specific research includes:

The Postmenopausal Estrogen Progestin Intervention (PEPI) Study, done in 1995, included about 900 women over a three year time period. This study concluded that hormone therapy raised HDL levels (the ''good'' cholesterol) and lowered LDL levels (the ''bad'' cholesterol).

The American Association of Clinical Endocrinologists' recent "statement on hormone therapy and cardiovascular risk, emphasizing that hormone therapy does not appear harmful in yourger women in early menopause and may indeed be beneficial to this group."

The Kronos Early Estrogen Prevention Study (KEEPS), which is currently underway and looks to "increase our knowledge about menopausal hormone therapy by helping scientific research determine if hormone therapy prevents or delays the onset of the number one killer of women, heart disease."