Perimenopause: Estrogen Deficiency in Disguise—And Why It’s Reversible

There’s a lot of mixed chatter about perimenopause, but much of it leaves women confused or even fearful. Let’s cut through the noise. Based on my years as a clinical hormone coach and decades of deep dive research into estrogen and estrogen-deficiency diseases, here’s the truth: perimenopause is not just about “getting older”—it’s about declining hormones, specifically estrogen.

Before we jump in, let’s quickly set the stage with the phases of menopause so you see the big picture:

• Pre-Perimenopause – Normal, regular menstrual cycling (typically ages 28–35).
• Premature Perimenopause – Women experiencing perimenopausal symptoms before late 30s (ages 28-35).
• Perimenopause – The transitional three-phase hormonal decline — early, mid, and late — leading up to the menopause. Each stage is marked by declining estrogen levels and rising FSH levels.
• Premature Menopause – The last menstrual cycle before age 40.
• Early Menopause – Menopause before age 45, often triggered by surgery or medical conditions.
• Menopause – Technically, the last menstrual period, though we only recognize it retroactively after 12 months without a menstrual period.
• Postmenopause – Everything after the menopause, which itself has three stages.

Perimenopause is often mischaracterized as a “normal life stage” or a vague transitional phase toward menopause, when in fact it is a predictable, progressive condition of hormonal deficiency—most notably, estrogen deficiency. The resulting symptoms are not random or simply “part of aging”; they are clinical manifestations of neuroendocrine disruption and a collapse in systemic hormone support that negatively impact nearly every organ system in the female body.

Contrary to popular belief, perimenopause is not inevitable or irreversible. When estrogen and progesterone are replenished in therapeutic doses administered cyclically to pre-perimenopausal blood levels, the symptoms of perimenopause dissipate—and in many cases, go away and are prevented for many years. This is what I have chosen to do for going on 18 years now.

The symptoms that many claim are caused by ‘perimenopause’ are really those of estrogen and progesterone deficiency.

What Is Perimenopause?

Perimenopause is a three-stage transitional process that a woman goes through leading up to the time her period has been missing for a year.

It can start as early as a woman’s early to mid-30s, though it more commonly begins in her early to mid-40s, and may last anywhere from 2 to 12 years. Unlike menopause, which is marked by 12 consecutive months without a period bleed, perimenopause has three phases characterized by irregular cycles, hormonal volatility, and the gradual failure of the ovarian-hypothalamic-pituitary axis to maintain adequate sex hormone production.

During this transition, ovarian estrogen output declines, and the corpus luteum frequently fails to produce sufficient progesterone. This hormonal instability disrupts the regulatory feedback loops between the brain and ovaries, altering the release of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and downstream neurosteroids.

The result? A cascade of symptoms often mistaken for psychiatric or age-related conditions.

Stages of Perimenopause

The best indicator to determine whether you are in the perimenopausal transition or your stage is your FSH level. FSH stands for follicle-stimulating hormone. It’s one of the key pituitary gonadotropins (along with luteinizing hormone, LH) that regulates ovarian function and female reproductive health.

• FSH is secreted by the anterior pituitary gland.
• Its primary role is to stimulate the ovarian follicles (tiny sacs in the ovaries that contain eggs) to grow and mature.
• As follicles develop, they produce estradiol (the most potent form of estrogen).

In other words, FSH drives estrogen production.

The stages of perimenopause are measured by FSH levels,

1. Early-Stage — FSH between 6-25
2. Mid-Stage — FSH between 25-45
3. Late-Stage — FSH between 45-60

How to Measure Perimenopause

Perimenopause isn’t just a mystery you have to “guess” at—it can be measured and tracked. The gold standard of predicting perimenopause includes:

1. Estradiol blood serum test – Healthy reproductive levels range from 300–500 pg/mL, depending on when you test your hormones. Perimenopausal women often fall well below this.
2. FSH blood test – Think of FSH as your brain’s estrogen barometer. Low estrogen = rising FSH. Levels between 6–35 indicate Stage I Perimenopause.
3. Clinical indicators – Symptoms such as irregular cycles, PMS, mood changes, brain fog, insomnia, weight gain, cravings, anxiety, depression, loss of confidence, low libido, and even executive function decline.

The dominant medical narrative holds that perimenopause is a time of "hormonal fluctuation"—as if the problem were simply the chaotic rising and falling of hormones. But this obscures the reality that the mean levels of estradiol steadily decline during perimenopause, especially during anovulatory cycles that become more frequent as ovarian reserve diminishes.

Estrogen, particularly estradiol (E2), is not just a reproductive hormone. It plays a critical role in nearly all physiological systems:

• Neurological: Modulates serotonin, dopamine, glutamate, norepinephrine, and GABA signaling. Decline leads to mood instability, anxiety, cognitive dysfunction, and loss of motivation.
• Cardiovascular: Regulates vascular tone, endothelial function, and cholesterol metabolism. Decline increases the risk of hypertension, dyslipidemia, and atherosclerosis.
• Musculoskeletal: Supports bone density and muscle strength. Deficiency accelerates osteopenia and sarcopenia.
• Metabolic: Influences insulin sensitivity and fat distribution. Estrogen deficiency promotes visceral fat gain and insulin resistance.
• Immunologic: Estrogen regulates inflammatory responses and immune modulation. Low estrogen contributes to autoimmune flares and systemic inflammation.

The hundreds of symptoms of perimenopause reflect these hormone deficiency side effects, such as:

• Anxiety and depression
• Mental illness
• Sleep disturbance
• Brain fog and memory loss
• Menstrual dysfunction
• Migraine or tension headaches
• Weight gain (especially abdominal)
• Night sweats and hot flashes
• Hair thinning, nails breaking
• Vaginal dryness, yeast infections, and urinary tract infections
• Loss of libido, sexual function decline
• Fatigue, apathy, failure to thrive
• Joint and bone pain
• Muscle atrophy and organ malfunction

These are not “normal” signs of aging—they are estrogen withdrawal symptoms. And this is the short list.

What Actually Causes Perimenopause?

The simple answer: estrogen deficiency.

Estrogen is the master messenger hormone for women. When levels remain at pre-perimenopausal levels, the brain gets the signal that reproduction is still in play. When estrogen stays low for too long, the brain gets the opposite message: the ovaries are winding down, and the body enters transition mode—perimenopause. This is not dictated by age. Any woman at any time can experience this decline for a multitude of reasons. I’ve seen many women in their late 20s experience stage I perimenopause.

Reframing Perimenopause: A Treatable Estrogen Deficiency Syndrome

Medical culture often pathologizes women’s responses to perimenopause with psychiatric labels or dismisses them as part of the female burden of aging. But when understood correctly, perimenopause is an estrogen deficiency syndrome with systemic consequences—and it is highly responsive to therapeutic-dose HRT treatment.

While conventional hormone replacement therapy (HRT) often emphasizes "low and slow" or “lowest effective dose” strategies, such approaches fail to completely restore the body to physiologic balance. They mitigate only surface symptoms without correcting the underlying insufficiency. Worse, many women are told they are "too young" for hormone therapy or are offered antidepressants or contraceptives instead—both of which can further suppress endogenous hormone production.

Estrogen and Progesterone Replacement—Physiologic Dosing Is the Key

To reverse the condition of perimenopause, hormones must be replaced in physiologic, therapeutic doses—not low doses that merely mask symptoms, but to fully restore optimal blood serum levels that mimic a pre-perimenopausal hormonal profile.

• Estradiol should be delivered by whatever HRT method yields pre-perimenopausal blood serum levels, such as injections or concentrated rhythmic transdermal compounded creams. 
• Oral progesterone should be administered cyclically on days 14-28 to protect the endometrium and support GABAergic brain activity, and help regulate the menstrual cycle. 

Restoring hormones to the reproductive, pre-perimenopausal range—not suppressing them—is the clinical goal. There is a technique and a process for full hormone restoration, so it’s important to work with a hormone team trained in advanced HRT protocols. There is a significant difference in clinical outcomes between low-dose HRT and therapeutic-dose HRT.

Preventing and Reversing Perimenopause: A New Standard of Care

It is time to abandon the outdated, passive approach to perimenopause and menopause care. A woman experiencing estrogen deficiency—regardless of her age—deserves hormone replenishment intervention that restores physiologic function, not dismissive reassurances or sedating drugs.

It will not be long until women figure out that they are being underdosed and will demand full hormone restoration. Advanced hormone therapy, when prescribed and administered correctly, addresses the hormone deficiency at the cause, which restores a woman’s ability to think clearly, lead confidently, sleep deeply, love fully, and live vibrantly.

Perimenopause is not a life sentence. With proper evaluation, targeted lab testing, and therapeutic-dose hormone replacement guided by a trained clinical hormone coach, women can reclaim hormonal health and avoid the descent into full menopause altogether.

The important takeaway: perimenopause is reversible and preventable. If estrogen and progesterone levels are fully restored and maintained at pre-perimenopausal reproductive ranges, the transition does not get triggered.

_References

_{Agarwal S, Alzahrani FA, Ahmed A. Hormone Replacement Therapy: Would it be Possible to Replicate a Functional Ovary? Int J Mol Sci. 2018;19(10):3160.}

_{Formby B, Schmidt F. Efficacy of biorhythmic transdermal combined hormone treatment in relieving climacteric symptoms: a pilot study. Int J Gen Med. 2011; 4:159-63.}

_{Harlow, Siobán D et al. “Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging.” Menopause (New York, N.Y.) vol. 19,4 (2012): 387-95.}

_{Hegazy, A. A. (Jan. 01, 2020). Is There any Means to Postpone The Menopausal Ovarian Senescence? International Journal of Fertility & Sterility, 13, 4, 346-347.}

_{Nagel, MD, James. Estrogen: A Girl's Best Friend. Dog Ear Publishing, 2018.}

_{Rhoades FP. The Menopause, A Deficiency Disease. Mich Med. 1965; 64:410-2.}

_{Roshenshein B. Preventing Menopause, Stopping Ovarian Failure Before It Starts. Your Health Press 2013.}

_{Walf, A. A., & Frye, C. A. (2006). A review and update of mechanisms of estrogen in the hippocampus and amygdala for anxiety and depression behavior. Neuropsychopharmacology, 31, 1097–1111.}