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Is Bioidentical Hormone Replacement Therapy Safe?

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The hormonal changes that women’s bodies go through during the middle and later stages of their lives can be significant. Fortunately, the understanding around what is happening inside the body due to menopause has come a long way, and doctors can now address the changes and decreases in hormones with an effective solution. Bioidentical Hormone Replacement Therapy, or BHRT, is used by many—but is it safe?


Hormone Replacement History

As far back as 11th century China, Taoist physicians were concentrating the urine from young men and women and making it into pills for emperors and empresses to live longer. It was documented that these high society men and women looked younger than others.

Fast forward to the 20th century in America when the pharmaceutical industry developed and popularized Premarin® (pregnant mare urine) to alleviate the unwanted symptoms of perimenopause and postmenopause in human females. In 1966 the famous Nurses’ Health Study was published, which followed nearly 60,000 women through menopause. The New England Journal of Medicine concluded, “we observed a marked decrease in the risk of major coronary heart disease among women who took estrogen with progestin.” Postmenopausal Estrogen and Progestin Use and the Risk of Cardiovascular Disease | NEJM

Many other studies have since come out demonstrating the incredible benefits of HRT for aging women. Then in 2002, an early finding was published from the largest HRT study to date (Women’s Health Initiative, WHI) stating that after just ten years of the fifteen-year study it would need to be halted due to the high rate of breast cancer in one of the arms of the study involving women ages fifty to seventy-nine. Suddenly, doctors across the country pulled their female patients off HRT without offering any solutions for their hormonal suffering. As ‘approved’ HRT was declining, a handful of doctors in the United States were beginning to have bioidentical progesterone and estrogen made by compounding pharmacies for those female patients that were yanked off their hormone therapy and were suffering.

In 1997, a book titled Natural Hormone Replacement for Women over 45 written by Dr. Wright and Morgenthaler, was published summarizing the safe uses of BHRT. Since that time many studies demonstrating the safety and efficacy of BHRT have been published. One of my favorites is: The bioidentical hormone debate: are bioidentical hormones (estradiol, estriol, and progesterone) safer or more efficacious than commonly used synthetic versions in hormone replacement therapy? – PubMed (

Understanding Menopause Symptoms

Starting as early as thirty-five years of age, women can suffer from symptoms associated with menopause:

  • Hot flashes
  • Night sweats
  • Mood swings between anger and sadness
  • Vaginal dryness
  • Sagging skin
  • Stiffness
  • Brain fog
  • Low libido
  • Hair loss
  • Unwanted hair growth
  • Weight gain
  • Thinning bones

In addition to hormone changes or hormone decline, some of these symptoms can also be due to aging. Are we aging because our hormones decline? Or is hormone decline a natural part of the aging process? Are hormones the fountain of youth? Nearly fifty percent of postmenopausal women in the United States use HRT. However, we can absolutely age gracefully without sex hormones (estrogens, progesterone, and testosterone). The foundational measures for aging gracefully are also the same foundational measures that I discuss when helping women who are using BHRT to optimize their response to the hormones. These measures are:

  • Adequate sleep
  • Low saturated fat and low carbohydrate diet (Plant based-paleo style)
  • Breathing exercises and rest
  • Regular and consistent bouts of exercise (cardio and resistance training)
  • Joy/sense of purpose
  • Balance all other aspects of your health such as thyroid, GI, and adrenal glands

The Safety of Bioidentical Hormone Replacement Therapy 

Bioidentical hormone replacement therapy is the use of hormone preparations that are derived from natural substances. Learn more in my previous post: What is Bioidentical Hormone Therapy?

Boldly, I say, bioidentical hormone therapy is safe for most women in most cases. It’s important to know the difference between HRT and BHRT. Hormone replacement therapy generally refers to the use of any hormones. Bioidentical hormone replacement therapy refers to the use of hormone replacement that has been derived from natural sources (wild yam or soy).

Further, BHRT involves the use of bioidentical hormone preparations and they are used in bioidentical routes of administration. The most bioidentical way to use bioidentical hormones is topically; either through creams, oils, vaginal applications, etc. In this way, the parent hormone is absorbed through the skin and circulates around the body first, before going to the liver for first pass detoxification.

Conversely, when you swallow hormones, they do not circulate as parent hormones, rather, they go to the liver first and enter into first pass metabolism and then the metabolites of the parent hormone circulate around the body. Naturally, our ovaries are not in our digestive tract and therefore most of the hormone that circulates from ovarian secretion is as the parent hormone.

There are situations in which BHRT is not safe for a patient and these typically include patient history of ER/PR positive breast cancer (BCA), ovarian cancer, endometrial cancer, endometriosis, and a few other circumstances. A wonderful reference book for more information about the safety of estrogen replacement: Estrogen Matters by Avrum Bluming, MD.  It does a great job at dispelling myths and fears around the use of HRT for women.

How Long Can BHRT be Used?

Many patients want to know how long they can use BHRT. What I tell my patients is that if I am recommending it now, then I am giving the green light to take these hormones to your grave. Otherwise, I would not be recommending it. In my opinion, if the use of hormones is not safe for the long haul, then it should not be prescribed at all.

I am pleased to report that the North American Menopause Association (NAMA) has updated their timeline and position on the prescription and use of HRT:

“NAMA, through its review of the literature that the previous position that hormone therapy should be prescribed only for the ‘lowest dose for the shortest period of time’ may be inadequate or even harmful for some women, has been changed to the more fitting concept of the ‘appropriate dose, duration, regimen, and route of administration’ that provides the most benefit with the minimal amount of risk. In addition, women older than 65 years old will be relieved to know that they don’t have to stop using hormone therapy for their bothersome hot flashes just because of their age. The data simply do not support it, but individualized evaluation and discussion is recommended.” (Source: North American Menopause Association)

When Are Bioidentical Hormones Appropriate?

Changes in a woman’s cycle typically start as early as thirty-five years of age. The changing time around a woman’s cycle is called peri (around) menopause. Menopause is defined by the calendar when a woman goes twelve months without a uterine bleed. Postmenopause is the time after that twelve months and lasts generally for about five years. Therefore, women may need hormone support from age thirty-five and up. My philosophy is that I meet women where they want to be met. If they want to age gracefully without hormones, I can help with that and support it. If they want to use hormone replacement, I will help with that too. I am in support of women using bioidentical hormones in a bioidentical application where it is safe and appropriate.

Foundational health is key for the optimization of the hormone treatment as well as overall health. Hormones won’t make you lose weight, sleep better, or reverse the clock of aging. What BHRT will do is resolve hormone related symptoms, slow the aging process, help to optimize your baseline health, and help to prevent diseases of aging. For the most part, BHRT is safe for women under the direction of a naturopathic doctor or physician.

Call to make an appointment with Dr. Kelly Parcell to discuss Bioidentical Hormone Replacement Therapy: 303-884-7557.