Is Hormone Therapy Safe?
The 2002 Hormone Myth And What Science Says Now.
Why your mother was told to stop her hormones, and what we know now…
“My mom stopped her hormones the week that study came out, and she never stopped being scared of them. I am not sleeping, have low energy and I do not know who to believe about hormone safety.”
This statement we hear more often than not. Most women in their forties and fifties grew up with the idea that hormone therapy was dangerous. Very few could tell you though where that data actually came from, it’s something their doctor told them. The fear is built around a study the was never designed to answer the question that most women were afraid of.
The fear began in 2002, when the Women’s Health Initiative released early results from this large hormone trial. The headlines focused on breast cancer, heart attacks and strokes. This headline struck fear for doctors who stopped prescribing hormones by 80 percent overnight, and a generation of doctors after that were trained in that shadow.
What got lost was who was in the study.
The average participant was in her mid-sixties, about a decade past menopause, and most of them were not having symptoms. They were given a horse-derived estrogen, Conjugated equine estrogen, combined with a synthetic progestin, which was the standard treatment at the time, not what is commonly used now.
In 2024 review in Obstetrics & Gynecology by two longtime menopause specialists, Dr. Barbara Levy and Dr. James Simon, makes a point we would like to share with you. For more than twenty years, results from one group of older women on one drug combination were applied to every woman and every hormone product.
Not all hormones behave the same way. We would never assume that every blood pressure medication works identically, so hormones are not different. The estrogen in the 2002 study came from pregnant mares’ urine and contains a mix of compounds, some of which women do not make at all. Estradiol, the form most commonly prescribed now, is chemically identical to the estrogen women ovaries produce, and the two act differently on the body, including on inflammation and vascular plaques. The same goes for progesterone, the synthetic progestin used in the trial has effects that bio-identical progesterone does not seem to share.
The studies show women who start hormone therapy right after menopause appear to have the most benefit. The Danish trial that followed women who began hormones right at menopause, the risk of heart attack, heart failure and death dropped by 52 %. Reviews of the research suggest about a 30 percent lower risk of dying from any cause, and the FDA has pointed to studies linking hormone therapy to 35% lower risk of Alzheimer’s, and 64% reduction in cognitive decline.
So why did the 2002 study look so different?
Part of the answer is in the arteries. Estrogen keeps blood vessels flexible and helps decrease plaque build up. Once estradiol is gone, plaque can start to accumulate, and the average woman in the WHI 2002 trial was 63, which often meant a decade or more without protection. The hormone they used in the study was Conjugated equine estrogen, made from horse urine, and it raises an enzyme called MMP-9 that breaks down collage, the material holding the cap over the plaque in place. When the cap weakens, plaque can rupture and trigger a heart attack. That’s what drove the jump in heart events in the first year of the study. What rarely gets mentioned is what happened next. After the first year, heart events dropped, and by the time the trial ended, the women on hormones had a lower risk than women on placebo. Estradiol, the bio-identical estrogen, more commonly used today, does not raise MMP-9 like conjugated equine estrogen, which is one of more reasons the WHI 2002 results do not tell us about the hormones women are offered now.
This is where a lot of articles get muddled, they lump everything together as “clotting risk.” Plaque build-up in the arteries and blood clots in the leg veins are two different problems with different causes. Being past 60 years old does not automatically rule a woman out. It means you need a doctor who understands the difference, who looks at your whole health before starting and who can talk through what the research does and doesn’t show for women who start later.
Is it right for you?
The rules are slowly catching up. In November 2025, the U.S Food and Drug Administration announced it was removing most of the “black box” warning that had sat on estrogen products since the early 2000s, and moving toward labels that consider a women’s health history. Health Canada has not made the same change yet, so you may still see that warning here. The Society of Obstetricians and Gynaecologists of Canada welcomed the U.S decision, and its guidelines already describe hormone therapy as safe to start for most healthy women at menopause.
How We Can Help
For most healthy women, hormone therapy is worth a serious look, and many who assume they can’t, may actually be good candidates once we have reviewed their history. The only way to know what fits you is hopping on a call with our team to answer your questions and see if its right for you. We take a look at the whole picture, hormones are a piece of the puzzle, not the whole picture. Book a complimentary call with our team.