Hormone Safety & Science
Evidence-Based Hormone Therapy: Clinical Evidence, Delivery Routes & Risk Analysis
If you search the internet for "hormone therapy," you will quickly run into two extreme opinions:
Some sources claim hormone therapy is completely dangerous and causes disease.
Others claim bioidentical hormones are 100% natural and carry zero risk at all.
Neither claim is true.
The medical research actually shows something much more specific: the exact hormone you take, and how you take it, changes everything.
At Greenwich Precision Health, we don't believe in blind fear or blind optimism. We follow the scientific evidence. Here is a clear breakdown of what the major studies actually found—and how we protect your safety.
1. The Cancer Myth: Real Progesterone vs. Synthetic Progestins
In 2002, a massive study called the Women’s Health Initiative made national news when it reported a link between hormone therapy and breast cancer. Doctors panicked, and millions of women stopped their treatment.
But here is the detail that got lost in the headlines:
The study didn't test real, bioidentical hormones. It tested estrogen paired with a synthetic chemical called MPA (a progestin).
Later, researchers looked closer at the data:
Women who took estrogen alone actually showed lower breast cancer rates.
A major French study following 80,000 women found that women taking real bioidentical progesterone had no increase in breast cancer risk, while those taking the synthetic version did.
The takeaway? The synthetic chemical was the issue, not the natural hormone.
2. Delivery Method: Pills vs. Skin Creams & Patches
It isn't just what you take—it’s how you take it.
When you swallow a hormone pill, it goes straight to your stomach and passes directly through your liver. Processing hormones through the liver increases clotting factors in your blood and can put extra stress on the body.
When you take hormones through the skin (a patch, cream, or gel) or by injection, they absorb directly into your bloodstream—skipping the liver altogether.
For Estrogen: Studies show that swallowed estrogen pills increase blood clot risks, while bioidentical estrogen absorbed through the skin carries virtually no increased risk.
For Testosterone: Old-fashioned synthetic testosterone pills were tough on the liver. Modern bioidentical testosterone given through skin gels or injections bypasses the liver completely.
3. How We Approach Compounded Hormones
You may have heard the term "compounded hormones." A compounding pharmacy is a specialized pharmacy that makes custom hormone doses tailored specifically to your body.
Some clinics claim compounded hormones are "magical" or completely risk-free. We take a more balanced, honest approach.
FDA-Approved Options First: Many bioidentical hormones (like certain estrogen patches or natural progesterone capsules) are available directly from standard pharmacies and are FDA-approved. When an FDA-approved option fits your needs, we use it.
Custom Compounding When Needed: When your body needs a very specific dose or combination that standard drug companies don't make, we use a trusted, highly vetted compounding pharmacy partner.
Compounding on its own doesn't make a hormone safer. What makes treatment safe is close physician oversight—using regular bloodwork, tracking symptoms, and adjusting your doses over time.
The Three Rules of Safe Hormone Therapy
Whenever you evaluate hormone therapy, remember these three rules:
The Molecule Matters: Natural bioidentical molecules behave differently in your body than synthetic look-alikes.
The Delivery Route Matters: Absorbing hormones through the skin or via injection is gentler on your liver and blood vessels than swallowing pills.
The Patient Matters Most: There is no "one-size-fits-all" dose. Your history, your bloodwork, and your personal goals guide every decision we make.