Journal / Women's Health Initiative

Disputing the Original WHI Research Findings

Nancy L. Belcher

Medically reviewed by Nancy L. Belcher Ph.D, MPA

Written by Winona Editorial Team

Last updated November 25, 2021

Disputing the Original WHI Research Findings

While it never feels good to suggest that someone else’s research is flawed, I do have to dispute the original Women’s Health Initiative research findings. As a scientist, I am frustrated by the continued spread of misinformation related to these inaccurate WHI research findings. 

There is a clear discrepancy between the published results from the Women’s Health Initiative study (Women’s Health Initiative), estrogen therapy side effects, the actual data from the study, and how misinformation about the study is being used to sell products 30 years later.

The Women’s Health Initiative transformed how women age, and not necessarily for the better. The Women’s Health Initiative study inaccurately identified estrogen therapy side effects and a relationship between the use of estrogen therapy and the risk for heart disease and breast cancer.3 

These findings continue to be echoed over and over on the internet even though they are imprecise, outdated, and were reversed by the Women’s Health Initiative study researchers themselves. People just trying to sell their ‘natural’ products will ignore the latest scientific studies. They dredge up this old, outdated information and amplify it on the internet in order to sell a product, not to provide scientifically proven relief.1,2  Some of the ‘natural’ products actually have harmful side-effects and few standards to prove they actually work. Negligent vendors use the old data to scare women away from using safe, effective, and thoroughly reviewed Hormone Replacement Therapy (HRT).

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Women’s Health Initiative

The original Women’s Health Initiative began in 1991 and lasted until 2005. In the years since the final data of this first study was released, Women’s Health Initiative researchers have worked hard to clarify that their summaries about the impacts of hormone replacement therapy and estrogen therapy were indeed flawed.1,2

The Women’s Health Initiative continues to research women’s aging in new studies and has revised their statement about HRT for menopause to read, “Hormone therapy is an option for some women to help relieve symptoms that occur early in menopause.1,2 Further, they stated that women on estrogen replacement therapy were not more likely to die than those who are not on HRT and that the health risks of taking HRT are very low.3,4,5

Most women don’t know about the updated Women’s Health Initiative results, they may have read about the original study results and therefore fear HRT. The estrogen therapy treatment that Winona is providing in 2021 is vastly different from the estrogen used in the old study called ‘Premarin’ (conjugated equine estrogens extracted from pregnant horse urine, PREgnant MAres uRINe).1,5-11 

Premarin is not a bioidentical hormone and is very different from what the female human body produces. Humans produce only three types of estrogens (estradiol, estriol, and estrone), whereas horses make over 21 types. When Premarin is used, a woman receives a combination of 21 types of estrogens, including 18 types that are not made by humans.1  Winona’s bioidentical hormones are completely different from the hormones used in the Women’s Health Initiative and have been shown to be much safer.

After the Women’s Health Initiative report was published, many physicians and researchers called for an independent review of the Women’s Health Initiative findings. Beyond the type of estrogen prescribed, the Women’s Health Initiative original research findings had many other flaws. For example, in order to study heart disease, researchers enrolled older women. Women who had been in menopause for as long as 30 years. Some women in the study were nearly 80 years old. 

We now know that if estrogen treatment is provided in a woman’s ‘40s and ‘50s, the risk of heart disease will decrease.8 However, the Women’s Health Initiative reported an increase in heart disease in these much older women who had spent decades at very low estrogen levels. Therefore, the Women’s Health Initiative conclusions were not accurate. Current studies suggest that in menopausal women, bioidentical estrogen and progesterone use may be associated with lower breast cancer risk compared to synthetic progestin.8 Micronized progesterone (Prometrium) is a bioidentical hormone with a molecular structure identical to the progesterone produced by the ovaries – this is what Winona prescribes. On the other hand, synthetic progestins, like Provera (medroxyprogesterone), have different chemical structures from progesterone made by the ovaries.

The other thing the Women’s Health Initiative did not evaluate was the quality of life improvements for women when taking HRT. The Women’s Health Initiative data actually showed that there was a clear benefit to HRT that outweighed possible risks for most women, especially in early menopause.5 

Health Benefits to HRT

There are many proven health benefits to HRT. We know that providing estrogen and progesterone HRT inhibits tumorigenesis (the development of tumors), and represents a strategy to prevent breast cancer.3 Data consistently shows that women on HRT can improve bone health, mood, wellness, and reduce cancer and mortality in the range of 30%.4,5,6 We also know that Winona HRT can offset many of the side effects of menopause including hot flashes, weight gain, skin dryness, sleeplessness, depression and so much more, without the risks identified in the original Women’s Health Initiative study.  

The enormous damage inflicted on generations of menopausal women due to the misinformation produced by the Women’s Health Initiative was unnecessary. Menopause is not just a women’s issue; untreated menopause symptoms can affect a woman’s family, her ability to work and parent, and can lead to relationship breakdown, and careers (even lives) are lost.  

Disputing the Original WHI Research Findings article body

Winona is here to help women progress through and beyond menopause and to spare them the unnecessary symptoms of menopause by providing each client with safe and effective, individualized therapy for their menopause symptoms. 

A note about those vendors who continue to push the inaccurate WHI reports. The outdated Women’s Health Initiative misinformation that scares women away from HRT is often pushed to the top of google search lists by manufacturers to sell their ‘natural’ products. These ‘natural’ products may have harmful side effects and few standards. By US law, there is no FDA evaluation or review process for the products they are pushing. It is simply up to the manufacturer to ensure that the over-the-counter (OTC) ‘natural’ supplements they sell are safe.4 It benefits them to continue to perpetuate the old, inaccurate Women’s Health Initiative claims to peddle their products.

Prescription products, like Winona’s HRT, have been thoroughly reviewed, proven safe and effective for their intended use before any sales to consumers are allowed. Prescription products are considered “drugs” because they are designed to treat medical conditions. They can only be prescribed by a medical professional and can only be dispensed by a pharmacy. Prescription products also have to be approved by the FDA and must pass several phases of clinical trials determining safety first and then efficacy.6 This same level of scrutiny is not necessary for OTC products.

“This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.”


  1. Nearly 3,700 articles written about this research project.




  5. J Womens Health 1997 Newton, KM

  6. Henderson, BE, nArch Intern Med, 1991; 151: 75 – 78

  7. Chen, WY Arch Intern Med. 2006; 166: 1027–1032








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