Perimenopause vs Menopause: Hormonal Changes, Symptoms, and What’s Normal

Written By jennifer hill

If you’ve been thinking…

  • “Why do I feel more anxious than I used to?”

  • “Why can’t I sleep even when I’m exhausted?”

  • “Why does my body feel unfamiliar lately?”

  • “Am I depressed… or is this hormonal?”

I want you to know this first: you’re not making it up, and you’re not “too sensitive.”

For many women, the transition from perimenopause into menopause can feel like your nervous system has a mind of its own. Mood changes, sleep disruption, irritability, brain fog, and shifts in weight or energy are incredibly common—and they’re often rooted in real hormonal changes happening behind the scenes.

This post will walk you through what’s happening (in a clear, evidence-based way), what’s considered normal, and when it’s worth reaching out for support.

What is perimenopause?

Perimenopause is the transition phase leading up to menopause. It often begins years before your final period—commonly in your 40s, sometimes in your late 30s.

Many women expect perimenopause to look like “a few hot flashes and then your period stops.”
But in real life, it often shows up as:

  • cycles changing (heavier, lighter, closer together, farther apart)

  • worsening PMS symptoms

  • sleep issues

  • mood changes (anxiety, irritability, tearfulness)

  • brain fog

  • new sensitivity to stress

Perimenopause is often the most symptomatic stage because hormones can become more unpredictable, not just lower.

What is menopause?

Menopause is defined as 12 consecutive months without a menstrual period, as long as it isn’t caused by pregnancy, certain medications, or another medical condition.

The average age of menopause in the U.S. is around 51.

After menopause, you’re in postmenopause, when hormone levels are generally lower but more stable.

Perimenopause vs menopause: what’s the difference?

Here’s the simplest way to think about it:

  • Perimenopause = hormone fluctuation + cycle changes

  • Menopause = periods stop + hormones settle into a new baseline

Perimenopause can feel like a roller coaster. Menopause can feel like the ride has ended—but your body is still adjusting to the new terrain.

The hormonal changes that drive perimenopause and menopause symptoms

Your ovaries and brain are constantly communicating through a hormone feedback loop. As ovarian function naturally shifts over time, your brain tries to compensate—and that creates changes in multiple hormones.

Let’s break down the main ones.

Estrogen (estradiol): the “everything hormone” you didn’t know you had

Estrogen (especially estradiol) plays a role in much more than reproduction. It impacts:

  • mood and emotional regulation

  • temperature control (hot flashes)

  • sleep quality

  • brain function and focus

  • skin and collagen

  • vaginal tissue and lubrication

  • bone density

  • cholesterol and cardiovascular markers

What happens to estrogen in perimenopause?

One of the biggest misconceptions is that estrogen simply “drops.”

In early and mid-perimenopause, estrogen often becomes erratic—it may spike higher than usual some months and then crash lower in others. That fluctuation is one reason symptoms can feel intense and unpredictable.

What happens to estrogen in menopause?

After menopause, estrogen is typically lower and more stable, which can contribute to symptoms like vaginal dryness and changes in body composition.

Progesterone: the calming hormone that often declines first

Progesterone is produced after ovulation. In perimenopause, ovulation becomes less consistent—so progesterone is often the first hormone to noticeably decline.

Progesterone has a calming influence on the nervous system, so when it drops, you may notice:

  • more anxiety or a “wired” feeling

  • irritability or emotional sensitivity

  • worse PMS symptoms

  • disrupted sleep (especially waking in the middle of the night)

A lot of women describe this phase as:
“I don’t feel like myself.”
And that’s not just emotional—it’s physiological.

FSH: the brain’s “try harder” signal

FSH (follicle-stimulating hormone) is released by the pituitary gland to tell the ovaries to mature follicles.

As ovarian response becomes less predictable, the brain often releases more FSH to compensate.

This is why FSH may rise during late perimenopause and menopause—but it can fluctuate earlier on, which is why a single test doesn’t always confirm what you’re experiencing.

Testosterone: yes, women need it too

Women produce testosterone through the ovaries and adrenal glands. Over time, levels may gradually decline and contribute to:

  • lower libido

  • reduced motivation or drive

  • lower muscle mass over time

  • fatigue

This doesn’t happen the same way for every woman, but it can be part of the overall hormonal picture.

Common perimenopause and menopause symptoms (and why they happen)

Hormones influence the brain, the nervous system, metabolism, and sleep. So symptoms can show up in ways that don’t always scream “hormonal.”

Hot flashes and night sweats

Hot flashes are linked to changes in the brain’s temperature regulation centers, influenced by estrogen changes.

You may notice:

  • sudden warmth or flushing

  • sweating

  • a racing heart

  • waking up drenched at night

Night sweats can be especially draining because they disrupt sleep—often leading to worsened mood, anxiety, and fatigue.

Sleep disruption: “I’m tired, but I can’t stay asleep”

Sleep changes are one of the most common complaints in perimenopause.

Women often describe:

  • waking at 2–4am

  • light, restless sleep

  • feeling exhausted but alert

  • increased nighttime anxiety

This can be influenced by:

  • night sweats

  • progesterone changes

  • increased stress sensitivity

  • changes in sleep architecture with age

And once sleep is disrupted, everything else gets harder—emotion regulation, cravings, motivation, patience, focus.

Anxiety, irritability, and mood changes

This is a big one—and it deserves to be taken seriously.

Hormonal fluctuations can increase vulnerability to:

  • anxiety

  • irritability (sometimes rage that feels out of character)

  • tearfulness

  • low mood

  • worsening PMS or PMDD symptoms

Estrogen influences neurotransmitters like serotonin and dopamine, which are involved in mood regulation. That’s one reason the emotional experience of perimenopause can feel so intense.

Important note: Women with a history of anxiety, depression, or postpartum depression may be at higher risk for mood symptoms during this transition.

Brain fog and concentration issues

Brain fog can feel scary. Many women report:

  • forgetfulness

  • word-finding difficulty

  • reduced focus

  • feeling mentally “slower”

This can be tied to:

  • disrupted sleep

  • chronic stress

  • estrogen fluctuations

  • mood changes

The good news: for many women, cognitive symptoms improve as hormones stabilize.

Weight changes and body composition shifts

Many women notice:

  • increased abdominal fat

  • more difficulty losing weight

  • reduced muscle tone

  • increased cravings or appetite changes

This isn’t just “getting older” or “not trying hard enough.” It’s often influenced by:

  • reduced muscle mass over time

  • sleep disruption

  • stress hormones

  • changes in insulin sensitivity

  • estrogen’s role in fat distribution

Your body may need a new approach in this season—especially strength training, protein support, and nervous system regulation.

Vaginal dryness and painful sex

Lower estrogen can affect vaginal tissue and urinary health. This is sometimes called genitourinary syndrome of menopause (GSM).

Symptoms can include:

  • dryness or burning

  • pain with sex

  • recurrent UTIs

  • urinary urgency or frequency

This is common and treatable—but many women don’t mention it unless asked.

What stage am I in? (A simple overview)

Early perimenopause

  • cycles may still be regular

  • PMS worsens

  • anxiety increases

  • sleep becomes lighter

  • subtle hot flashes may start

Late perimenopause

  • skipped periods

  • unpredictable bleeding patterns

  • more noticeable hot flashes/night sweats

  • mood and sleep symptoms intensify

Menopause and postmenopause

  • estrogen remains lower and more stable

  • hot flashes may improve over time

  • vaginal/urinary symptoms may increase without treatment

  • bone density loss accelerates early after menopause

Can hormone tests confirm perimenopause?

Sometimes labs can help—but symptoms and cycle patterns often tell us more.

Because hormones fluctuate significantly during perimenopause, labs can look “normal” even when symptoms are very real.

A clinician may check labs to rule out other causes of symptoms, such as:

  • thyroid dysfunction

  • anemia or iron deficiency

  • vitamin deficiencies

  • sleep apnea

  • medication side effects

When to seek support (you don’t have to white-knuckle this)

Perimenopause is natural. But struggling in silence shouldn’t be the expectation.

Consider reaching out if you’re experiencing:

  • persistent insomnia

  • panic symptoms or worsening anxiety

  • depression or loss of joy

  • severe irritability

  • heavy bleeding or bleeding between periods

  • painful sex or frequent UTIs

  • symptoms impacting your work, relationships, or daily life

There are evidence-based options that can help—including lifestyle strategies, non-hormonal medications, hormone therapy for appropriate candidates, and targeted support for vaginal/urinary symptoms.

The best plan is always individualized.

FAQ: Perimenopause and menopause

How long does perimenopause last?

Perimenopause often lasts several years, commonly 4–8 years, though every woman’s timeline is different.

What hormone drops first in perimenopause?

Often, progesterone declines first, because ovulation becomes less consistent.

Can perimenopause cause anxiety?

Yes. Hormonal changes can increase anxiety symptoms and stress sensitivity in some women.

Can perimenopause cause depression?

It can. Some women experience new or worsening depression symptoms during the transition—especially those with a personal history of mood disorders.

How do I know if it’s hormones or thyroid issues?

Symptoms can overlap. A clinician may evaluate thyroid function and other labs to rule out medical causes.

Final thoughts

The perimenopause-to-menopause transition is not “all in your head.” It’s a real neurohormonal shift that can affect mood, sleep, metabolism, and how your body responds to stress.

If you’re feeling unlike yourself, you’re not alone—and you don’t have to push through it without support.

At Inner Balance, my goal is to help women feel grounded, informed, and supported through this transition with evidence-based care that considers the whole picture.

References (Evidence-Based Sources)

  • North American Menopause Society (NAMS)

  • American College of Obstetricians and Gynecologists (ACOG)

  • Endocrine Society

  • National Institute on Aging (NIH)

jennifer hill
Next

Depression During Perimenopause