HRT vs. Breast Cancer

Happy Thursday!

Yesterday, I wrote about testosterone replacement therapy and the myths around prostate cancer in men.

Today, I want to continue that conversation, but shift it to women.

If men have been misled for decades about the safety of optimizing their testosterone, women have arguably had it even worse.

Hormone therapy in women was all but demonized after the Women’s Health Initiative (WHI) created a wave of fear that still hasn’t fully dissipated 20 years later.

Doctors pulled millions of women off their hormone therapy overnight, terrified of “causing” breast cancer.

But when you go back and look at the data with modern eyes, it becomes obvious the WHI was misinterpreted, misrepresented, and misused.

The fear it created robbed an entire generation of women of vitality, sexual health, and peace of mind.

And now, finally, the truth is starting to come out.

How the WHI Misled Millions of Women

The Women’s Health Initiative, published in 2002, was supposed to be a landmark study on HRT. Instead, it became one of the most damaging missteps in modern medicine.

The study combined estrogen with a synthetic progestin (not bioidentical progesterone, and certainly not testosterone).

Yet the headlines that followed claimed “hormones cause breast cancer” as if all forms of hormone therapy were the same.

The nuance was lost, the damage was done, and millions of women were abruptly cut off from therapies that made them feel alive.

In the years that followed, countless women suffered unnecessarily.

Doctors were taught to fear hormones.

In the decades since, multiple large analyses have shown that properly administered HRT does not increase breast cancer risk.

In fact, some data suggest it may reduce it.

Testosterone is a Female Hormone

When people hear “testosterone,” they think of men.

Muscle, aggression, drive.

But every woman on earth makes testosterone.

In fact, women produce more testosterone than estrogen by volume across their lifespan.

Testosterone is responsible for energy, mood stability, bone health, sexual desire, and even cognitive sharpness. When it starts to decline (usually in the late 30s and 40s) women experience fatigue, irritability, stubborn fat gain, insomnia, and loss of libido.

Yet most women have never even had their testosterone levels checked.

And even fewer have been told that they can safely restore them.

Testosterone replacement therapy, when done at physiologic doses (not the bodybuilding kind), is one of the most powerful longevity tools available, for both men and women.

Moreover, multiple long-term studies have shown that women on testosterone therapy actually have lower rates of breast cancer than those who do nothing.

Lower Breast Cancer Incidence with Testosterone

Over the past 15 years, several major clinical cohorts have followed thousands of women receiving testosterone therapy.

The results are nothing short of astonishing.

In one 9-year study of more than 2,300 women treated with pellets (not my preferred method, but it’s better than nothing), only 14 cases of invasive breast cancer were reported.

That’s a 35% lower incidence than in age-matched women not on testosterone.

Then came the 15-year Dayton study.

It was a prospective follow-up of over 1,200 women on long-term testosterone therapy.

Their breast cancer rate was 189 cases per 100,000 women per year, compared to 355 per 100,000 in the general population.

That’s nearly a 50% reduction in breast cancer incidence.

The researchers didn’t expect this outcome.

They were studying symptom relief, yet what they found was something more profound.

Women who optimized their testosterone were living longer and getting less cancer.

What About Women Who Already Have or Had Breast Cancer?

Here’s where it gets even more interesting.

Historically, any woman with a past diagnosis of breast cancer was told to avoid hormone therapy at all costs. The assumption was that any hormones would feed cancer.

But modern clinical data tell a very different story.

In a study following women who had been treated for breast cancer and were suffering from severe menopausal symptoms, testosterone therapy improved their quality of life dramatically.

And over years of follow-up, there were no increases in recurrence rates.

One study even followed 72 breast cancer survivors treated with testosterone for nearly a decade.

Not one recurrence was observed.

In women who have or have had breast cancer, testosterone therapy can be a lifeline.

Beyond Cancer

For women in their 40s, 50s, and beyond, testosterone therapy can be a lifeline.

It supports lean muscle mass and bone density, helping prevent the frailty and osteoporosis that plague so many postmenopausal women.

It enhances cognitive performance, sharpens focus, and supports mood stability.

It restores libido and improves sexual satisfaction (one of the most common yet least discussed challenges women face during and after menopause).

In clinical studies, women receiving testosterone report better sleep, fewer hot flashes, improved motivation, and a sense of feeling like themselves again.

Multiple controlled trials have shown measurable improvements in physical function, energy, and mood, even in women who previously tried estrogen alone and saw no relief.

If estrogen is the nurturing, restorative hormone, testosterone is the life force.

It is the drive, the spark, the sense of presence that makes a woman feel grounded in her body again.

The Rebirth of HRT

For decades, HRT was almost a dirty phrase in medicine. Women were told to just accept the symptoms of aging, or to take antidepressants for fatigue and loss of desire.

But the tide is turning. Modern endocrinology now understands that HRT is safe and beneficial.

It can improve quality of life, protect the heart and bones, and in the case of testosterone, even reduce the risk of breast cancer.

The tragedy is that the fear instilled by the WHI still lingers in the minds of many physicians.

They remember the headlines, not the data.

They remember the warnings, not the follow-up analyses that completely changed the interpretation of those results.

Today, thousands of women around the world are rediscovering what hormone balance truly feels like.

They’re reclaiming their energy, their sexuality, their clarity.

It’s time the world catches up with the data.

Closing Thoughts

Testosterone therapy for women is not experimental, it’s not fringe, and it’s not dangerous.

It’s one of the most thoroughly studied interventions in modern hormone science.

And across every dataset we have, the data shows women who restore healthy testosterone levels live longer, feel better, and experience fewer cases of breast cancer than those who don’t.

After decades of misinformation and fear, it’s time to return to truth.

Best,

Hunter Williams

Further Reading

• 10-Year Study: Testosterone Therapy & Lower Breast Cancer Risk — Glaser et al., BMC Cancer (2019)
  https://bmccancer.biomedcentral.com/articles/10.1186/s12885-019-6457-8

• 15-Year Update: Testosterone Reduces Breast Cancer Incidence — Glaser et al., Gavin Publishers (2024)
  https://www.gavinpublishers.com/assets/articles_pdf/Incidence-of-Invasive-Breast-Cancer-in-Women–Treated-with-Testosterone-Implants-Dayton-Prospective-Cohort-Study-15-Year-Update.pdf

• Testosterone Therapy Shows 35–40% Lower Breast Cancer Rate — Glaser et al., Maturitas (2013)
  https://www.sciencedirect.com/science/article/pii/S0378512213002545

• Topical Testosterone Boosts Sexual Function in Survivors — Taranto et al., Breast Cancer Research (2024)
  https://breast-cancer-research.biomedcentral.com/articles/10.1186/s13058-024-01886-7

• Low-Dose Testosterone Keeps Estradiol Stable in Patients — Taranto et al., ResearchGate Preprint (2024)
  https://www.researchgate.net/publication/380483093_Evaluation_of_efficacy_and_effect_of_topical_low-dose_testosterone_3_mgmL_on_estradiol_levels_by_mass_spectrometry_in_breast_cancer_patients_receiving_ovarian_suppression_and_aromatase_inhibitor_thera