By Peter A. McCullough, MD, MPH
The perimenopausal and menopausal times for women to say the least, are complicated. So I brought in an expert to give us an update.
🩺 Perimenopause and Menopause — A Hormone-Focused Summary
Dr. Peter McCullough hosts Dr. Jennifer Pfleghaar, a board-certified DO in Emergency Medicine and Integrative Medicine, for a deep dive into the hormonal architecture of perimenopause and menopause. Dr. Pfleghaar, author of The Perimenopause Reset, practices virtually outside Nashville and brings both clinical rigor and hard-won personal experience — she achieved remission from Hashimoto’s thyroiditis after conventional medicine told her nothing could be done.
🔬 The Physiology: What’s Actually Happening
Perimenopause is the transitional window before full menopause (defined as complete cessation of menstrual cycles for 12 months). During this phase, the hormonal landscape becomes chaotic:
Progesterone undergoes a slow, steady decline. This is the hormone dominant in the luteal phase (second half of the cycle), responsible for calming GABA receptor binding, sleep quality, and mood stabilization.
Estradiol (estrogen) does not decline smoothly — it becomes erratic and spiky. Feedback signaling from the hypothalamic-pituitary-ovarian axis degrades, producing what Dr. Pfleghaar likens to “static” in the system.
The widening gap between declining progesterone and fluctuating estradiol creates a state of functional estrogen dominance, even when absolute estrogen levels are falling.
Dr. Pfleghaar emphasizes that women entering perimenopause with pre-existing metabolic dysfunction — insulin resistance, impaired estrogen clearance via liver/gut pathways — will experience more severe symptoms. She considers the menstrual cycle a vital sign: heavy bleeding, severe cramping, and disabling PMS in younger years are warning signals of trouble ahead.
💊 The Three-Hormone Approach
Progesterone — First Line
Progesterone replacement is typically the starting point in perimenopause. Dr. Pfleghaar strongly prefers oral bioidentical progesterone, taken at night, because first-pass hepatic metabolism converts it into allopregnanolone — a neurosteroid that binds GABA receptors and produces calming, sleep-promoting effects.
Timing: Cyclical administration only — taken during the luteal phase (approximately days 15–28 of the cycle), not continuously.
Dosing: Typically 100–200 mg compounded extended-release. Younger women may start at 50 mg while root causes are addressed.
Exceptions: About 5% of women experience paradoxical agitation or excessive sedation from oral progesterone. For these patients, topical application bypasses the allopregnanolone pathway.
Safety note: Oral progesterone does not produce toxic hepatic metabolites, unlike oral estrogen.
For women earlier in perimenopause with milder deficiency, Dr. Pfleghaar may trial Vitex (chaste tree berry), contained in Venus from TWC, to support endogenous progesterone production before committing to bioidentical replacement.
Testosterone — Adrenal-First, Then Replace
Testosterone in women derives predominantly from the adrenal glands, not the ovaries. Therefore, low testosterone often reflects adrenal depletion from chronic stress or cortisol dysregulation rather than a primary gonadal failure.
Workup priority: Optimize adrenal function and stress management first. Labs often show testosterone rebounding once cortisol is controlled — without any exogenous hormone.
When to replace: Roughly one-third of perimenopausal women and a higher fraction of postmenopausal women ultimately need supplementation — but only after ruling out stress-driven deficiency.
Administration: Topical only. Dr. Pfleghaar starts at 0.25 mg topically per day, compounded in a VersaBase cream, applied to inner thigh or arm for 60–90 seconds. She rarely exceeds 0.75 mg.
Why not oral: First-pass hepatic metabolism produces toxic metabolites. Oral testosterone is contraindicated.
Why not pellets: Dr. Pfleghaar is unequivocally opposed to hormone pellets. They deliver supraphysiologic, uncontrolled doses, cannot be removed, and produce a crash cycle. They are, she notes, typically administered after minimal training at med spas.
Monitoring: Serum testing is unreliable with topical administration. Dr. Pfleghaar uses saliva testing to assess tissue-level hormone load and correlates with symptom resolution.
She highlights a critical safety point: high-dose testosterone in the absence of adequate estradiol creates cardiovascular risk — a phenomenon observable in the transgender population receiving testosterone with estrogen suppression.
Estrogen — Topical, Bioidentical, and Metabolically Aware
Estrogen replacement enters the picture primarily in late perimenopause and postmenopause. Dr. Pfleghaar’s approach is shaped by the estrogen metabolism pathway framework:
Pathway Outcome Good Safe excretion, no DNA damage Bad Inflammatory metabolites Ugly Genotoxic metabolites — cancer risk
Route: Topical (transdermal) is preferred. Oral bioidentical estrogen undergoes first-pass hepatic metabolism, stressing the liver and producing the “ugly” metabolites associated with DNA damage and carcinogenesis. Sublingual/troche routes are second-line because some is inevitably swallowed.
Monitoring: Serum levels often fail to reflect tissue load with transdermal administration. Saliva testing reveals cases of significant overdosing — Dr. Pfleghaar describes postmenopausal patients with painful, tender breasts from excessive estrogen that serum labs missed entirely.
Duration: Indefinite. Women who discontinue lose bone, cardiovascular, and cognitive protection. Dr. Pfleghaar frames this as a lifelong commitment to health preservation, not a temporary intervention.
She draws a sharp distinction between bioidentical hormones (estradiol, progesterone) and synthetic hormones (conjugated equine estrogens, progestins). The Women’s Health Initiative’s adverse outcomes — thrombosis, breast cancer, cardiovascular events — reflect the use of synthetics and progestins, which bind receptors but produce opposing physiological effects (e.g., progestins constrict blood vessels where bioidentical progesterone relaxes them).
🔑 Core Principles
Hormone replacement is not one-size-fits-all. Every woman’s “oven” preheats and cooks differently. Treatment must be individualized based on labs, symptoms, and metabolic context.
Root cause must precede replacement. Metabolic health, stress, and liver/gut function determine how well a woman tolerates hormonal fluctuations and clears estrogen metabolites.
Synthetic is not bioidentical. The distinction is not semantic — it determines cardiovascular, thrombotic, and oncologic risk profiles.
Route matters. Topical estradiol and testosterone avoid first-pass hepatic toxicity. Oral progesterone uniquely delivers neurosteroid benefits.
Monitoring requires the right tool. Saliva testing captures tissue-level hormone activity that serum testing misses with transdermal preparations.
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Peter A. McCullough, MD, MPH
President, McCullough Foundation
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📚 Reference
Pfleghaar, J. The Perimenopause Reset. Available at: Amazon
Website: https://www.integrativedrmom.com/
