Bio-identical Hormone replacement: The facts and fiction

By Charles A Evans MD

Your body is composed of a variety of different hormones, which carry messages between your organs and cells. Hormones are secreted by glands in your endocrine system to help the body stay balanced and function optimally. Aging is associated with a loss of sex hormones in both men and women. Replacing these lost hormones can restore lost feelings of well-being, sex drive, energy levels and reverse bone and muscle loss associated with aging. Our goal is to improve quality of life into old age by using hormone replacement therapy when needed.



Estrogen is found in greater amounts among women. Its main function in the body is growth and development. It stimulates growth of fat cells and the inner lining of the uterus called the endometrium. There are three different forms of estrogen: estradiol, estrone and estriol. Estradiol is considered to be the main player during most of a woman’s reproductive life. This is replaced by the more “toxic” estrone just before menopausal symptoms begin, with falling levels of all estrogens. Estrogen is considered essential for brain health, and deficiencies result in hot flashes (thermoregulation) and problems with libido, memory, cognition and multitasking. Many women refer to this as “brain fog.” Estrogen also acts as an antidepressant, and deficiencies can lead to problems with mood swings and fatigue. In addition to its effects on the brain, estrogen deficiencies are also associated with hair loss, thinning of skin, premature wrinkles, and osteoporosis.



Progesterone performs a balancing act for estrogen. It antagonizes estrogen-driven growth of the inner lining of the uterus called the endometrium. It is also neuroprotective, and deficiencies are associated with increased anxiety and problems with sleep. Progesterone also strengthens bones and supports cholesterol and libido. An imbalance in the ratio of estrogen to progesterone, such as those occurring before menopause, can lead to many problems including weight gain, anxiety, bloating, fluid retention, headaches, excessive uterine bleeding and fibroid tumors of the uterus.



Testosterone plays similar roles in men and women, only men require ten times the amount. It supports libido, energy, bone density, memory and well-being. Deficiencies are associated with decreased libido, fatigue, muscle loss and accelerated weight gain. Too much testosterone can cause aggression, depression, impotence and excessive libido.


Facts and Fiction of Hormone Replacement

With every passing decade we are living longer and longer. Women can expect to live at least a third of their lives as postmenopausal. While women were initially expected to grin and bear the hot flashes, irritability and mood swings associated with post menopause, the arrival of hormone replacement therapy (HRT)

in the 1960’s liberated millions of women. At this time, synthetic estrogens were the standard therapy for women going through the “change.” It later became obvious that estrogen encouraged the growth of the uterine lining, which leads to increased risk of cancer. Premarin was the drug of choice and was derived from estrogen-like products found in horse urine. Progesterone was known to protect the uterus so the medical and pharmaceutical community promoted a synthetic, patentable form with similar effects on reproductive tissues. These were called progestins. Neither of these hormones were natural to the human body. The chemical structure of these hormones bear no resemblance to the hormones they were meant to be replacing.
Millions of women received symptomatic relief on these hormones. However, the long term effects were unknown until 2002 when the Women’s Initiative Study was published. This study included over 16,000 women and demonstrated an increased risk of death on these hormones. (JAMA 2002 Jul 17;288(3):321-33, JAMA 2004 Apr 14;291(14):1701-12) The risk of breast cancer almost doubled, and there was also significant risks from heart attacks and strokes. (JAMA 2010; 304(15):1684-1692) As a result of these findings, HRT was abandoned by many doctors and patients alike.

It appeared that no one stopped to think that these chemicals that had no similarity in molecular structure to natural human hormones might be toxic to the human body. Women using Premarin and synthetic progestins were found to have a 69% greater risk of developing invasive breast cancer over an eight year period compared to women not on hormone replacement. Those who used bio-identical estrogen and progesterone (chemical structures identical to human hormones) had no increased risk compared to those taking no hormone at all. (Breast Cancer Res Treat. 2008 Jan;107(1):103-111) Intuitively, this should not be surprising since these are exactly the same hormones that circulated through their bodies for four decades before they became menopausal. Additionally, no one bothered to monitor levels of these hormones prior to 2002 to make sure the levels in the doses used were in the same ranges as those seen in the normal menstrual cycle.
Studies demonstrate that even appropriate levels of bio-identical estrogen unopposed by progesterone supplementation decrease libido and increase the likelihood of fibrocystic breast disease, uterine fibroids, obesity, uterine cancer, and breast cancer. All of these undesirable effects of estrogen are countered by progesterone. One way to look at progesterone is that it puts the breaks on the growth properties of estrogen that can lead to disease and death. Restoring proper progesterone levels along with estrogen is what is known as restoring “hormone balance.” The finesse of this “balance” is taken one step further by adding just a pinch of testosterone. Once balanced, a woman can enjoy quality years of physical, mental and sexual wellness in a manner that is safe and natural. To achieve this balance, dosing changes based on hormone levels are required. The goal is to achieve hormone levels comparable to those seen from days 20-23 of the normal menstrual cycle in a 25 year old. Once achieved, levels are still recommended on a yearly basis along with a physical exam, mammograms, and bone density studies.

I always like to emphasize that breast cancer should be a concern for all women over 40. In this regard, the leading causes of breast cancer are obesity, genetics and aging. Even though studies show no increased risk on bio-identical hormone replacement, there remain other risk factors so that common sense dictates continued vigilance and screening.