Women under 50 now face an 82% higher cancer incidence compared to men in the same age group.
According to a recent report from the American Cancer Society, this gap has grown significantly. Back in 2002, the difference was just 51%.
If we’re living in the same environments, eating similar diets, and exposed to many of the same stressors, what’s driving the difference?
The answer lies in our hormones. Today, women are being exposed to higher amounts of estrogen than ever before. Women naturally have higher levels of estrogen compared to men. Estrogen encourages cell growth and division. This is needed for reproduction and pregnancy, but it can also stimulate the excessive cell division we see in cancer. When estrogen is chronically elevated, or not properly balanced by progesterone, it can create a hormonal environment that increases the risk for cancer.
There has been a steady rise in invasive breast cancer, which is often driven by estrogen and treated by blocking estrogen. Breast cancer has been increasing by about 1% each year since 2012, and by 1.4% annually in women under 50.
Uterine cancer is also on the rise, another hormonally-driven cancer. From 2013 to 2022 the death rate rose by 1.5% per year.
The report points to several possible contributors: higher rates of excess body fat, delayed childbirth, and having fewer children overall, but estrogen plays a role in all of these factors.
Normally estrogen is balanced by progesterone. In a healthy internal environment, cancer is rare in the young. But today, women are not only producing estrogen internally, but also being exposed to additional estrogens from environmental toxins, hormonal birth control, processed foods, and plastics. They are told to eat nuts, seeds, seed oils, and vegan diets high in polyunsaturated fats, all of which are estrogenic. This stacked exposure, on top of what the body already produces, can tip the balance and contribute to excessive cell growth, the foundation of many cancers.
The idea that estrogen can contribute to cancer often brings up a lot of strong reactions, especially in discussions around menopause. But it’s important to look at biology honestly. Imbalanced estrogen can cause cancer.
This doesn’t mean estrogen is inherently “bad.” It means its effects depend on context, balance, and timing.
Understanding this is part of engaging with complex biological realities. For example, in breast cancer treatment, estrogen blockers are sometimes necessary, not because estrogen has no value, but because at that moment, unregulated growth must be addressed first. Hormones are powerful, and recognizing both their strengths and risks is key.
Why do some in the menopause community claim estrogen is harmless?
Because much of the conversation is based on population-level outcome data, rather than mechanistic understanding. In other words, they’re often looking at broad observational studies, while I’m looking at what these hormones actually do at the cellular level.
Estrogen stimulates cell growth—that’s its nature. And unregulated cell growth is the basis of cancer.
This doesn’t mean outcome data has no value. But without understanding the underlying mechanisms, how estrogen interacts with receptors, influences mitochondrial function, or drives proliferation, we risk drawing incomplete or misleading conclusions. Population studies can guide questions, but mechanisms tell us why.
What factors are contributing to estrogen dominance and cancer?
- Early puberty leading to higher lifetime exposure to estrogen.
- High body fat, which produces its own estrogen via aromatase.
- Hormonal contraceptives that contain estrogen or synthetic progestin.
- Higher exposure to endocrine-disrupting chemicals (cosmetics and personal care products).
- Higher rates of hypothyroidism.
- Diets high in estrogenic foods like seed oils, nuts, seeds, and soy.
- Delayed childbirth & having fewer children overall. The high progesterone exposure during pregnancy offers a lifetime protective effect against cancer.
- Increased use of fertility treatments, which stimulate supraphysiologic levels of estrogen. Repeated or long-term use may contribute to increased cancer risk, especially in the ovaries and endometrium.
- Why isn’t estrogen impacting men the same way it is women, especially in terms of cancer?
- It comes down to balance, exposure, and stability.
Men naturally produce much lower levels of estrogen than women. So even when exposed to external estrogenic compounds, like plastics, soy, or endocrine-disrupting chemicals, their overall estrogen burden remains relatively low. Women, on the other hand, already have higher baseline levels of estrogen, especially during their reproductive years. When modern exposures are layered on top of this, it can push the body into a state of estrogen excess.
Another key difference is that women rely on progesterone to balance the effects of estrogen. Progesterone calms tissue growth, promotes differentiation, and keeps estrogen’s stimulatory effects in check. But unlike testosterone in men, progesterone levels fluctuate dramatically throughout a woman’s cycle and drop sharply with stress, disrupted ovulation, or hormonal birth control. This leaves many women with periods of unopposed estrogen, which increases the risk of hormone-sensitive cancers like breast, uterine, and ovarian cancer.
Testosterone in men, by contrast, is relatively stable. It doesn’t fluctuate monthly or cyclically the way female hormones do. This stability helps maintain a more consistent internal environment and protects against the kinds of hormonal imbalances that can drive excessive cell growth.
What can women do to lower their risk?
- Ensure estrogen is balanced with progesterone. In many cases, this may require supporting ovulation or supplementing with progesterone
- Limit exposure to endocrine-disrupting chemicals. Avoid plastics, synthetic fragrances, conventional cleaning products, and cosmetics with parabens or phthalates.
- Get sunlight and support vitamin D levels. Vitamin D helps regulate cell growth and may reduce the risk of breast, uterine, and ovarian cancers.
- Ensure adequate intake of nutrients like niacinamide, magnesium, vitamin A, vitamin E, and calcium support hormonal balance, lower inflammation, and promote metabolic health.
- Minimize unnecessary hormone use. Long-term use of hormonal birth control or synthetic hormone replacement therapy should be discussed carefully, especially if cancer risk is a concern.
- Support liver detoxification. The liver breaks down estrogen. Support it with b vitamins, adequate protein and carbohydrates.
- Prioritize restorative sleep. Poor sleep disrupts circadian rhythm, raises cortisol, and throws off hormone balance, especially progesterone.
“I don’t think people realize how much control they have over their cancer risk,” Rebecca L. Seigel, an epidemiologist with the American Cancer Society and the report’s first author, told the outlet. “There’s so much we can all do” (Schultz, 2025).