Hormones Explained Simply: What’s Actually Happening in Perimenopause?

by Megan Fain, PT

Founder, Power Reset Path

Last reviewed: August 2026

Estrogen.

Progesterone.

Testosterone.

Cortisol.

Insulin.

Melatonin.

Thyroid hormones.

If reading that list makes you want to close this page, stay with me.

You don’t need a biochemistry degree to understand your body.

And you definitely don’t need to memorize a giant hormone chart.

Let’s make this simpler.

First: What Is a Hormone?

Hormones are chemical messengers.

They’re produced in different parts of your body and travel through your bloodstream, carrying information that helps coordinate what happens next.

Think of your body as an ongoing conversation.

Your brain, ovaries, muscles, bones, reproductive tissues and other systems aren’t operating independently.

They’re communicating.

Hormones are part of that communication system.

And that’s why changing hormones can sometimes be felt in places that seem completely unrelated to your period.

So What’s Changing During Perimenopause?

During perimenopause, your ovaries begin functioning differently.

Ovulation becomes less predictable. You may ovulate during some cycles and not during others.

At the same time, production of ovarian hormones — particularly estrogen and progesterone — changes.

Estrogen can fluctuate considerably during the menopausal transition before eventually reaching much lower levels after menopause.

Progesterone is closely connected to ovulation. When ovulation becomes less frequent or doesn’t occur during a cycle, progesterone production changes too.

That’s part of the reason your periods — and some of the symptoms you experience alongside them — can become less predictable.

And it’s why reducing perimenopause to simply “low estrogen” doesn’t tell the whole story.

Your body is moving through a transition, not experiencing the failure of a single hormone.

Estrogen: More Than a Period Hormone

We tend to associate estrogen with reproduction.

But estrogen has effects throughout the body.

It plays roles involving your reproductive system, bones, brain and other tissues.

During perimenopause, changing estrogen production is associated with some of the hallmark symptoms of the menopausal transition, including hot flashes and night sweats.

After menopause, lower estrogen levels are also important to longer-term health considerations such as bone health.

So when estrogen changes, the effects aren’t necessarily limited to your menstrual cycle.

Progesterone: Closely Connected to Ovulation

Progesterone is produced after ovulation.

Its job during the menstrual cycle includes helping prepare the lining of the uterus for a possible pregnancy.

If pregnancy doesn’t occur, estrogen and progesterone levels fall and menstruation follows.

During perimenopause, ovulation becomes less predictable.

That means progesterone production can become less predictable too.

This is one reason menstrual patterns can begin changing during the menopausal transition.

What About Testosterone?

Yes, women produce testosterone too.

The ovaries and other tissues contribute to androgen production, and these hormones play roles in women’s health.

But testosterone isn’t the single explanation for every change in energy, muscle or sexual desire during midlife.

Those areas can be influenced by many things — including health conditions, medications, sleep, relationships, stress, aging and other physiological changes.

This is a good example of why we’re careful about assigning one symptom to one hormone.

Bodies are more complicated than that.

And What About Cortisol, Insulin, Melatonin and Thyroid Hormones?

These hormones matter.

But here’s an important distinction:

They aren’t all reproductive hormones driving the menopausal transition.

Cortisol is involved in your body’s response to stress.

Insulin helps regulate glucose in your bloodstream.

Melatonin helps regulate your sleep-wake cycle.

Thyroid hormones influence metabolism and many other body functions.

All of these systems continue operating while you’re moving through perimenopause.

That means your overall experience can reflect more than changing ovarian hormones alone.

For example, poor sleep may affect how you feel the next day.

Stress can influence your mood and your ability to cope with additional demands.

Thyroid conditions can cause symptoms that overlap with symptoms women sometimes attribute to menopause.

Your health is an interconnected system.

That’s precisely why we shouldn’t blame every midlife symptom on estrogen.

Do You Need to Test All of Your Hormones?

Usually, no.

This is another place where menopause information online can become unnecessarily complicated.

For many women in the typical age range, healthcare professionals can identify the menopausal transition based largely on age, symptoms and changes in menstrual patterns.

A single hormone measurement may not tell you very much because hormone levels can fluctuate unpredictably during perimenopause.

There are situations where testing may be appropriate — particularly when symptoms or menstrual changes occur at a younger age or when another health condition needs to be considered.

That’s a conversation to have with your healthcare professional based on your individual situation.

So Which Hormone Should You “Fix”?

This may be the wrong question.

Your body isn’t a dashboard where every hormone has an independent dial.

And you don’t need to spend your life trying to “balance” every hormone perfectly.

Instead, we can start with a different question:

What can I influence?

Movement.

Strength.

Nutrition.

Sleep habits.

Recovery.

Stress management.

Preventive healthcare.

And appropriate medical evaluation and treatment when symptoms warrant it.

Lifestyle strategies aren’t replacements for medical care, and some women benefit significantly from medical treatment for menopausal symptoms.

The goal isn’t to micromanage every hormone in your body.

It’s to understand what’s changing, support the health you can influence, and get appropriate care for the things that need more.

Understanding Creates Choices

Your hormones aren’t betraying you.

And your body isn’t a problem you need to solve.

It’s changing.

Understanding some of those changes gives you better information for deciding what comes next.

You don’t need to understand every biochemical pathway.

You don’t need to fix everything today.

You need good information, practical strategies, and the willingness to stay curious about your own body.

That’s where we start.

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Ready for Your Next Step?

Hormones are part of the story.

But they aren’t happening in isolation.

Next, let’s look at another system that can influence how you experience stress, sleep, overwhelm and everyday life during this transition.

→ Read: Your Nervous System in Perimenopause: Why Everything Can Suddenly Feel Like Too Much

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About the Author

Megan Fain, PT is a physical therapist, health educator, and founder of Power Reset Path. With more than 15 years of experience in healthcare and additional training in functional nutrition, Megan focuses on making complex health information understandable, practical, and useful for women navigating perimenopause and midlife.

She founded Power Reset Path on the belief that every woman, at every age, has an innate power to transform the world around her. Sometimes we just need help seeing it.

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A Note From Power Reset Path

This article is for education and general wellness information and isn’t a substitute for individualized medical care. Symptoms can have causes other than perimenopause. Talk with your healthcare professional about new, severe, persistent or concerning symptoms and about evaluation and treatment options appropriate for you.

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References & Further Reading

American College of Obstetricians and Gynecologists (ACOG)

The Menopause Years

Patient education about perimenopause, changing estrogen production, menstrual changes, menopause and treatment options.

American College of Obstetricians and Gynecologists (ACOG)

Do I Need to Have Testing of My Hormone Levels During Perimenopause?

Guidance about when hormone testing is — and isn’t — typically useful during the menopausal transition.

National Institute on Aging (NIH)

What Is Menopause?

Information about estrogen and progesterone changes, common symptoms and health changes associated with the menopausal transition.

Office on Women’s Health, U.S. Department of Health and Human Services

Menopause Basics

Information about changing estrogen and progesterone production, unpredictable ovulation, irregular periods and the menopausal transition.

The Menopause Society

Perimenopause

Patient education about changing ovarian hormone production, ovulation and menstrual patterns during perimenopause.