A plain-language, continually updated guide from Dr. Matt Chalmers’ clinical reference on hormones and peptides.
Estrogen refers to a group of related hormones — estradiol (the most potent and important one), estrone, and estriol — produced mainly by the ovaries before menopause, with fat tissue, muscle, skin, and even bone taking over as the main source afterward. Estrogen regulates the menstrual cycle, supports bone density, and influences cardiovascular and cognitive health.
Here’s something worth understanding that’s often skipped over: estrogen doesn’t exist independently — it’s built from testosterone. Every woman has to make testosterone before her body can convert it into estrogen, through a process called aromatization. That connection matters more than most people realize when hormone levels start to shift. It’s why we start with testosterone in women’s hormone care: when testosterone is where it should be, her body can naturally make its own estrogen. In our experience, that is often enough to resolve hot flashes, night sweats and vaginal dryness, which means less need for added estrogen and less worry about estrogen dominance.
“Estrogen retards osteoclastic function, which is bone breakdown. Testosterone activates osteoblastic cells that build bone back up. Yes, saving bone is good, however, it’s not going to help osteoporosis, since the bone has already broken down. So again we are back to them needing testosterone.”
— Dr. Matt Chalmers, The Pillars Path: A Root-Cause Guide to Hormones, Peptides, and Metabolic Health
In a normal cycle, estrogen builds up the uterine lining and progesterone balances it back down — the two work as counterparts. When estrogen is present without enough progesterone to oppose it (called “unopposed estrogen” or estrogen dominance), the uterine lining can keep growing unchecked. This isn’t just a theoretical concern: it’s the actual medical reason progesterone is added to estrogen therapy for women who still have a uterus, and it’s why any unexpected bleeding while on hormone therapy should always be reported to your provider — it’s usually the first sign worth checking, even though these changes often cause no symptoms at all.
Like other steroid hormones, estrogen synthesis begins with cholesterol. Its metabolism and clearance from the body also depend on adequate liver methylation capacity, supported nutritionally by B vitamins including folate, B12, and B6.
Estrogen is FDA-approved as a prescription therapy for specific indications, including menopausal hormone therapy. Use is determined through lab testing and individualized evaluation with our providers.
Estrogen is FDA-approved as a prescription therapy for menopausal hormone therapy, among other indications, and its documented physiological roles include effects on bone density, cardiovascular markers, and vasomotor symptoms (hot flashes) in clinical trial populations. Appropriateness is individualized based on health history and lab testing.
These are three related but distinct estrogen hormones with different potency and roles in the body; estradiol is the primary and most potent form during reproductive years.
This page draws on The Pillars Path: A Root-Cause Guide to Hormones, Peptides, and Metabolic Health by Dr. Matt Chalmers — Pillars of Wellness’ clinical reference on hormone and peptide therapy.
