Do You Love Progesterone as Much as I Do?

What is Progesterone?

Note: This is NOT about progestins or synthetic progestagens.The terms “progesterone” and “progestogens” are often used as catch-all labels for both natural and synthetic variants. This generalization is deeply misleading.

Of all progestogens, only one qualifies as natural: micronized progesterone. Natural progesterone has properties that differ significantly from those of synthetic progestins—a distinction that could protect your life.

The known beneficial effects of progesterone form a very long list. What follows is a focused overview of the most clinically significant ones.

Cancer Risk & Oncology

Estrogen stimulates cellular growth, especially in the endometrium—increasing proliferation and raising the risks of endometrial, ovarian, and breast cancers. Progesterone counteracts estrogen's effects and exhibits anti-proliferative properties.

Progesterone activates the p53 gene—when inactive or mutated, this gene fails to trigger natural cell death (apoptosis), increasing the risk of DNA damage and therefore cancer. Progesterone's activation of p53 is one mechanism by which it may offer oncological protection.

Progesterone use has also been linked to lower incidence of uterine and colon cancers, and may be beneficial in treating endometrial cancer, ovarian cancer, melanoma, mesothelioma, and prostate tumors.

Cardiovascular System & Blood Pressure

One important property of progesterone is its diuretic effect—it significantly reduces sodium and water retention and helps regulate blood pressure. (Note: BHRT using micronized progesterone may initially raise BP in some women before the vasodilatory effects take hold.)

Over time, progesterone causes vasodilation by increasing nitric oxide (NO), which causes blood vessels to relax and widen—improving blood flow. A 2021 study showed progesterone also helps prevent BP spikes triggered by adrenaline-like hormones. Its mechanism is similar to that of calcium channel blockers used to treat hypertension.

• Suppresses platelet aggregation
• Stabilizes blood sugar and plays a role in addressing insulin resistance and diabetes
• Prevents lipid peroxidation, offering vascular protection
• Has an anti-atherogenic effect
• Is being studied for traumatic brain injury (TBI) treatment in men, women, and children

Inflammation & Immune Health

Progesterone stimulates the release of Th2 cytokines (anti-inflammatory) and directly inhibits Th1 cytokines (pro-inflammatory). It reduces the activity of natural killer (NK) cells and inhibits matrix metalloproteinases (MMPs)—particularly MMP-9 and MMP-2—which are involved in autoimmune, inflammatory, and infectious diseases, as well as cancer and arthritis.

Progesterone is a known stimulator of IL-10, a cytokine with strong anti-inflammatory properties.

Key Roles & The Hormone Cascade

Progesterone is a precursor of all sex hormones and steroid hormones. Understanding this cascade explains why progesterone deficiency has such far-reaching consequences.

Progesterone is the true pro-gestational hormone—essential for implantation of the fertilized egg and for maintaining pregnancy. It is also an antioxidant that prevents lipid peroxidation by reducing malondialdehyde levels, a major marker of oxidative stress elevated in chronic heart failure, kidney disease, and endometriosis.

Additional clinically documented effects include: reduces epileptiform brain activity (used in epilepsy treatment), acts as a natural immunosuppressant in autoimmune conditions, mimics leptin secretion to reduce appetite and improve insulin sensitivity, and improves postpartum depression and PMS.

Deficiency & Estrogen Dominance

Starting around age 30, luteal progesterone production begins to decline, leading to luteal phase insufficiencyand a state of estrogen dominance. Because progesterone counteracts estradiol's effects in breast tissue and the uterus, its absence allows estrogen to go unchecked.

The correct approach to treating estrogen dominance in perimenopause and early menopause is a high dose of bioidentical progesterone—not hysterectomy. Progesterone should be the first-line treatment for women with symptoms of perimenopause or early postmenopause.

In contrast to synthetic progestins—which weaken estrogen's beneficial effect on lipid profile and carry androgenic side effects—natural progesterone exerts strong progestogenic and antiestrogenic effects on the endometrium without androgenic consequences. It protects coronary vessels, reduces cancer risk, and when combined with bioidentical transdermal estrogen, enhances its positive effects on lipid metabolism.