Bioidentical Hormones Side Effects

In 2002, the abrupt halt of the Women’s Health Initiative (WHI) left women fearing the side effects hormone therapy. Ten years later, experts, physicians and researchers are reexamining the incomplete results of this study, determining that these findings may not be so accurate after all.

It is important to note that the WHI tested the effectives of synthetic or traditional hormone therapy, not bioidentical hormones. Regardless, recent meta-analyses of the WHI study and other cohort studies have examined the long term effects of both, synthetic and bioidentical hormone therapies and have unveiled evidence that hormone therapy actually decreases the risk of disease.

Side Effects

This is not to say that either therapy is without a few potential side effects which are classically linked to dosage – as your hormone levels improve, your dosage may need to be changed. If you notice side effects, contact your physician.

  • Men and women have reported increased aggressiveness, acne or irritability during the initial phases of testosterone hormone therapy, but these issues are generally resolved as levels become balanced.
  • Some women have reported breast tenderness, spotting, cramping and bloating. These symptoms may be experienced initially with estrogen hormone treatment, but resolve as hormone levels become balanced.
  • Occasionally, hormone therapy patients will complain of itching or redness at the injection or insertion site, bit these symptoms diminish as the body adjusts to treatment.

FDA Approval

Many people are under the misconception that bioidentical hormones are not FDA-approved. This is simply not the case. The hormones derived from plant sources, such as soy and yams, are approved by the FDA, however the methods of delivery and custom doses are not.

Bioidentical hormones may be delivered in the form of creams, patches, pills, gels, pellets of vaginal rings. Bioidentical hormones are designed in a lab and shipped to a compounding pharmacy where they are custom designed to fit the needs of each patient. Synthetic hormones are created in specific, patented doses and delivery methods (not customized), therefore regulation is possible.


For those who may not be familiar with this study, the WHI was the largest long-term study of the effects of synthetic hormone therapy for women, which was prematurely halted in 2002 because many subjects were shown to have an increased risk of heart disease and osteoporosis. These inconclusive results left women fearful for their health and distraught over where to find relief from the symptoms of menopause.

In the March 2011 issue of the medical journal, Menopause, researchers conducted an in-depth analysis of the WHI study along with several more recent studies on HRT. One branch of the study analyzed the effects of HRT on the health of 71,000 women and uncovered statistics in opposition to the findings of the WHI study.

Analysis of the surveys from this study revealed that women aged 34 to 59 had a decreased risk of cardiovascular disease with the use of HRT, while women in the eldest category, aged 70 to 84, had no increase in their risk for heart disease while using HRT. Even in the WHI study, women who began HRT between the ages of 50 to 59 experienced a decreased risk of heart disease.

A November 2011 study took a closer look at the effects of discontinuation of HRT at varying points in the lifespan. This study analyzed the bone density of 50,000 women who were either on HRT or had discontinued use. These women were followed for 6½ years, during which time researchers observed a 55 percent increase in hip fractures amongst women who had discontinued HRT. Even more disconcerting was the steady decline of bone density each year for women who never returned to HRT.

These studies reveal that HRT does not increase the risk heart disease, but actually lowers it. Additionally, halting HRT increases your risk of osteoporosis and hip fracture – ultimately, it negatively affects bone density. I like to keep my patients aware of studies that offer analysis of multiple long-term research projects such as these – it makes it easier for individuals to make more informed decisions about their health.


The known associated risks of hormone therapy for men are minimal. There has been rumored to be an increased risk of prostate cancer, however advancements in delivery method and dose customization have reduced that risk. A 2006 study, compared men on testosterone therapy with men who were not and observed for the incidence of cancer. At completion of the study, 15.2 percent of men, who did not receive testosterone therapy, were diagnosed with cancer compared 14 percent of those receiving testosterone therapy.