Identical Hormones

Common Biologically Identical Hormones

Estradiol (E2)

Estradiol, the principal estrogen found in a woman’s body during the reproductive years, is produced by the ovaries. Estradiol may be very effective for the symptomatic relief of hot flashes, genitourinary symptoms, osteoporosis prophylaxis, psychological well-being and reduction of coronary artery disease.

Because it is much more potent than estriol, it might be more effective for symptomatic relief than estriol. When estradiol is replaced using a parenteral (sublingual, pellet implant, percutaneous, or transdermal) route, it may not be subject to first-pass metabolism by the liver, and therefore does not produce high levels of estrone. Using these routes of administration, a woman might be able to mimic the physiologic release of estradiol from the ovaries, thus receiving natural hormone replacement.

Estriol (E3)

Estriol is the weakest of the three major estrogens. In fact, it is 1,000 times weaker in its effect on breast tissue. Estriol is the estrogen that is made in large quantities during pregnancy and has potential protective properties against the production of cancerous cells.

An important article in the 1966 Journal of the American Medical Association by H.M. Lemmon, M.D., reported a study showing that higher levels of estriol in the body correlate with remission of breast cancer. Dr. Lemmon demonstrated that women with breast cancer had reduced urinary excretion of estriol. He also observed that women without breast cancer have naturally higher estriol levels, compared with estrone and estradiol levels, than women with breast cancer. Vegetarian and Asian women have high levels of estriol, and these women are at much lower risk of breast cancer than are other women. Estriol’s anti-cancer effect is probably related to its anti-estrone properties it blocks the stimulatory effect of estrone by occupying the estrogen receptor sites on the breast cells.

Estriol is the estrogen that may be most beneficial to the vagina, cervix and vulva. In cases of vaginal dryness and atrophy, which predisposes a woman to vaginitis and cystitis, topical estriol may be the most effective and safest estrogen to use. Because of this, estriol might be better than estradiol for the treatment of urinary tract infections.

None of the American drug products contain Estriol, so it is not available in most drug stores, although it has been used widely in Europe for over fifty years. Because estriol cannot be patented, it does not hold much interest for the pharmaceutical industry. Its availability through compounding has caused its use to grow rapidly throughout the country.

Estrone (E1)

Estrone is the estrogen most commonly found in increased amounts in postmenopausal women. The body derives it from the hormones that are stored in body fat. Estrone may do the same work that estradiol does, but it might be considered weaker in its effects.

Biest – (80%/20%) E3/E2)

Biest is a combination of two estrogens: estriol and estradiol. It is most commonly found in a ratio of 80:20, estriol to estradiol. This combination might allow for all of the protection of estriol, while potentially providing the cardiovascular and osteoporosis benefits and vasomotor symptom relief of estradiol.

Triest – (80%/10%/10%) E3/E2/E1

Triest is a combination of three estrogens: estriol, estradiol and estrone. It is most commonly found in a ratio of 80:10:10, estriol, estradiol, and estrone. This combination is very popular and contains all of the three major circulating estrogens. It may be slightly weaker in its effect when compared to biest. However, this may be compensated for by increasing the strength or by slightly changing the ratios.


Progesterone is produced by the ovaries and the adrenal glands in women and, in smaller amounts, in the testes and the adrenal glands in men. One of its most important functions is in the female reproductive cycle. Progesterone may prepare the lining of the uterus for implantation of a fertilized egg, then may help to maintain it during pregnancy. If pregnancy does not occur, it signals the uterus to shed this lining.

Progesterone also may play an important role in brain function and is often called the “feel good hormone” because of its potentially mood-enhancing and anti-depressant effects. Optimum levels of progesterone might signify feelings of calm and well-being, while low levels of progesterone may mean feelings of anxiety, irritability and even anger. Current research shows that progesterone may play a role in the maintenance of the nervous system, the sense of touch, and motor function.


Usually considered a male hormone or androgen, testosterone is also produced by women, although in much smaller amounts than in men. Testosterone works differently in the bodies of men and women, but it may play a very important role in the overall health and well-being of both sexes. Often called the “hormone of desire” because of its potentially powerful effect on libido, testosterone may also be important in building strong muscles, bones, and ligaments as well as a probable increase of energy and ease of depression. Low levels of testosterone might cause fatigue, irritability, depression, aches and pain in the joints, thin and dry skin, osteoporosis, weight loss, and the loss of muscle development.

As with all of the hormones, testosterone must be dosed properly to be effective without causing unwanted side effects. The dose in women is generally one-tenth that used in men. Because testosterone may not be effective when it is taken orally, it is usually prescribed as a topical gel or cream or as a sublingual tablet.


Pregnenolone might be a “superhormone” that is the key to keeping our brains functioning at peak capacity. Some scientists believe it may be the most potent memory enhancer of all time. Perhaps what is even more amazing are the studies that demonstrate pregnenolone may enhance our ability to perform on the job while heightening feelings of well-being. In other words, this hormone appears to make us not only smarter, but also happier.

Like the other steroid hormones, pregnenolone is synthesized from cholesterol. In a complex series of steps, cholesterol is broken down into different steroid hormones as the body needs them. It is first synthesized into pregnenolone and used by the body in that form. What is not utilized undergoes a chemical change that “repackages” it into DHEA. DHEA, in turn, is used by the body as DHEA and is also broken down into estrogen and testosterone. This chain of hormones is known as the “steroid pathway.” Because pregnenolone gives birth to the other hormones, it is sometimes referred to as the “parent hormone.”

Pregnenolone was studied extensively in the 1940s. It was shown to be beneficial in possibly elevating mood, improving concentration, fighting mental fatigue, improving memory and relieving severe joint pain and fatigue in arthritis. Pregnenolone may have vast therapeutic potential and is currently undergoing further studies.


Short for dehydroepiandrosterone, DHEA is a steroid hormone distinguished from others by its unique chemical structure. DHEA is produced by the adrenal glands (located just above the kidneys) as well as by the brain and the skin, and is the most abundant steroid in the human body.

As newborns, we have an extremely high level of DHEA, but within a few days after birth, our DHEA level drops to nearly zero. Then between the ages of six and eight, we experience the event called “adrenarche,” in which our adrenal glands begin to stir and gear up for puberty. At the same time, our DHEA level begins to rise steadily and continues to rise until it peaks at around age twenty-five to thirty. From that point on, it declines at a rate of about 2 percent a year, and we begin to feel the result of this decline in our mid-forties. By eighty, our DHEA level is only fifteen percent of what it was when we were twenty-five. This drop in DHEA levels correlates dramatically with the signs and symptoms associated with aging.

DHEA is currently the focus of some of the most exciting medical research of this century. Researchers at distinguished medical centers all over the country are studying the properties and promise of DHEA. It may be a potent protector against cancer. It might protect against heart disease by lowering blood cholesterol and preventing blood clots. Studies also demonstrate that DHEA may improve memory, strengthen the immune system, prevent bone loss, and may even protect us from diabetes and autoimmune disease. It may aid in the fight against fatigue and depression; it also might enhance feelings of well-being and might increase strength. DHEA may alleviate symptoms of menopause, reduce body fat, and might even enhance libido.

Biologically Identical Hormone Links & Resources