Study shows bioidentical hormones are superior to synthetic HRT

Research by the American Osteopathic Association has found strong evidence showing bioidentical hormones that are approved by the FDA are safer and more effective than standard hormone replacement therapy.

A report in the Journal of the American Osteopathic Association is based on studies of literature published between 1999 and 2009 into the use of bioidentical hormone replacement therapy to treat menopausal symptoms (such as hot flashes).

The study looked at clinical trial evidence regarding the safety and efficacy of bioidentical hormones.

It notes bioidentical hormones are derived from plant sources and are termed ‘bioidentical’ because it is claimed they are structurally identical to natural hormones. Bioidentical hormone replacement therapy is sometimes referred to as natural hormone replacement therapy.

Women’s Health Initiative trial results

In July 2002, the principal results of the Women’s Health Initiative (WHI) trial were published in The Journal of the American Medical Association. The trial involved more than 160,000 postmenopausal women aged 50 to 79 – looking at hormone replacement therapy as well as low-fat diet, and calcium plus vitamin D supplementation to prevent heart disease, breast cancer, colorectal cancer, and fractures.

The women received either the most commonly prescribed HRT in the United States at the time — 0.625 mg of CEEs and 2.5 mg of medroxyprogesterone acetate (MPA) (sold under the brand name Prempro) — or a placebo.

After 5 years, the women who had been receiving the estrogen and progestin combination were found to have a 26% increased risk of breast cancer, 29% increased risk of myocardial infarction or death from cardiovascular disease, 41% increased risk of cerebral vascular accident, 200% increased risk of venous thrombotic disease/embolism, deep vein thrombosis, and pulmonary embolism.

There was also a 33% decreased risk of hip fracture, 37% decreased risk of colorectal cancer, and reduction of reported menopausal symptoms.

The trial concluded continuation of HRT would result in more risks than benefits. HRT was stopped by many women or their physicians across the United States after the WHI results were published, and women and physicians have been seeking alternative therapies ever since.

Bioidentical hormone replacement therapy is different

Bioidentical hormone replacement therapy is fundamentally different from standard HRT because the hormones are identical to those that naturally occur in the body. Bioidentical hormome therapy hit the headlines in 2006 after actress Suzanne Somers published a best-selling book called ‘Ageless: The Naked Truth about Bioidentical Hormones’.

The book claimed women could gain back a lean body, shining hair and glowing skin as a result of taking bioidentical hormones, as long as they were also eating correctly and exercising in moderation. Millions of Americans became aware of her book and her ideas when she appeared on The Oprah Winfrey Show in January 2009, where she presented her BHT regimen. So let’s look more closely at bioidentical hormones and what the study found.


17β-Estradiol is by far the most studied bioidentical estrogen. It is approved by the FDA for the management of many menopausal symptoms, vulvar or vaginal atrophy, hypoestrogenism, and prostate cancer; prevention of osteoporosis; and palliation in metastatic breast cancer. More recently, researchers have been investigating a variety of other possible uses.

Results of small-scale studies show 17β-estradiol appears to have an anti-depressant effect.

Estriol (E3)

The efficacy of estriol in relieving menopausal symptoms as well as HRT does, has been established in small-scale clinical trials. A study of 74 postmenopausal women who had vaginal atrophy were treated with estriol or a placebo for 16 weeks; positive benefits of estriol treatment were found at clinical and colposcopic examinations. There were no reported side effects of the well-tolerated treatment.


Two branded forms of bioidentical progesterone are approved by the FDA. The first, Crinone, was approved in 1997 and is used during in vitro fertilization. The second, Prometrium, was approved in 1998 for relief of postmenopausal symptoms and for the prevention of endometrial hyperplasia. In a randomized double-blind, placebo-controlled trial of Prometrium, 358 postmenopausal women were treated with either 200 mg of Prometrium per day for 12 days, or a placebo. The Prometrium resulted in a substantially lower rate of endometrial hyperplasia.

Additionally, there is limited evidence that progesterone may have some neuroprotective properties. In a small, 100-patient study reported in 2007, patients presenting to the emergency room with acute traumatic brain injury were randomized to receive either progesterone intravenously or placebo intravenously, and blinded observers evaluated the patients’ neurocognition. Patients in the treatment group had a lower mortality rate at 30 days, and patients with an injury classified as moderate were more likely to have a good outcome.


The use of testosterone in women has been controversial. Although a variety of testosterone therapies and products are approved by the FDA, they are approved for use in women only for the palliative treatment of metastatic breast cancer and, with 2 branded formulations combined with estrogen, for the treatment of menopausal vasomotor symptoms. The largest efficacy trial to date studied the use of testosterone to treat hypoactive sexual desire disorder in 814 women over a 52-week period.

In a randomized fashion, women received a transdermal patch that delivered either 150 μg/d or 300 μg/d testosterone or a placebo patch. None of the women were taking estrogen products. When compared with placebo, testosterone at both doses increased desire and decreased distress; the number of satisfying sexual episodes in any given 4-week period was greatest in the women who received 300 μg/d testosterone. The most frequently reported adverse event was unwanted hair growth.


The American Osteopathic Association report notes the Food and Drug Administration has adopted a cautious stance towards bioidentical hormones and does not recognize them as different from those used in standard HRT. It attaches risk to all estrogens and progesterones/progestins – based on the WHI trial – until proven otherwise.

However, the research found bioidentical hormone therapy — including estrone, 17β-estradiol, and progesterone — offers better results and safety than standard HRT for managing menopausal symptoms. It found further studies are needed to confirm the safety and efficacy of estriol, DHEA, and testosterone in women.

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