If you’re wondering why you suddenly feel anxious, exhausted, irritable, forgetful, or unlike yourself, you’re not imagining it.

You may be experiencing perimenopause.

For many of us, perimenopause arrives quietly and then gradually begins to affect everything from sleep and mood to periods, energy, and confidence.

Yet despite affecting millions of women, it remains widely misunderstood.

Let’s break down what perimenopause actually is, what is happening hormonally, and why no two experiences look exactly alike.

What Is Perimenopause?

Perimenopause is the transitional phase leading up to menopause.

During this time, the ovaries begin to change how they function, leading to fluctuating hormone levels and a wide range of symptoms.

Menopause itself is just one point in time.

It is officially reached when you have gone twelve consecutive months without a menstrual period.

Perimenopause is the journey that gets you there.

This transition can begin several years before menopause, often in a woman’s 40s, although some women experience it earlier.

During this phase, fertility gradually declines, menstrual cycles become less predictable, and symptoms may begin to appear.

The Hormonal Story: More Chaos Than Decline

Many people believe perimenopause is simply a gradual drop in estrogen.

In reality, the hormonal picture is much more complicated.

During perimenopause, estrogen does not steadily fall.

Instead, it fluctuates dramatically.

Some days or months levels may be higher than they were in your younger years.

At other times they may drop sharply.

Think of it less like a gentle slope and more like a roller coaster.

At the same time:

• Ovulation becomes less consistent.
• Progesterone production often declines earlier because progesterone is produced after ovulation.
• Estrogen levels become increasingly unpredictable.
• Testosterone may gradually decrease.
• The brain works harder to coordinate communication between the ovaries and reproductive hormones.

These fluctuations affect many systems throughout the body, not just the reproductive organs.

Why Hormones Affect So Much More Than Periods

Estrogen receptors exist throughout the body, including in the:

• Brain
• Heart and blood vessels
• Bones
• Muscles and joints
• Skin
• Bladder
• Vaginal tissues
• Gut

That means changing hormone levels can influence far more than menstrual cycles.

Periods may become:

• Heavier
• Lighter
• Closer together
• Further apart
• More unpredictable

For many women, changing periods are the first noticeable sign of perimenopause.

Sleep Problems

You may find yourself:

• Waking during the night
• Struggling to fall asleep
• Feeling unrefreshed despite sleeping

Poor sleep often becomes one of the most disruptive perimenopause symptoms because it can amplify nearly every other symptom.

Mood Changes

Women commonly report:

• Increased anxiety
• Irritability
• Feeling overwhelmed
• Lower resilience to everyday stress
• Episodes of low mood

These changes are not a sign of weakness or a lack of coping skills.

Hormonal fluctuations can directly affect neurotransmitters involved in mood regulation.

Brain Fog

Many women describe:

• Forgetting words
• Losing their train of thought
• Difficulty concentrating
• Reduced mental sharpness

This can be especially frustrating for women managing careers, families, and other responsibilities.

Hot Flushes and Night Sweats

These symptoms occur because hormonal changes can affect the body’s temperature regulation system.

Some women experience occasional flushes.

Others experience them multiple times a day and throughout the night.

Physical Changes

Other symptoms may include:

• Joint aches
• Headaches
• Breast tenderness
• Weight changes
• Fatigue
• Changes in libido
• Vaginal dryness
• Bladder symptoms

The list can feel surprisingly long because hormones influence so many interconnected systems.

Why Does the Perimenopause Experience Vary So Widely?

One woman may sail through perimenopause with minimal symptoms.

Another may feel as though every aspect of her physical and emotional wellbeing has been disrupted.

BOTH EXPERIENCES ARE NORMAL.

Several factors influence how perimenopause is experienced.

Every Woman Starts From a Different Baseline

Your genetics, hormone sensitivity, medical history, and overall health all shape how your body responds to hormonal change.

Two women with similar hormone levels may experience completely different symptoms.

Hormone Fluctuations Matter More Than Hormone Levels

For many women, it is not simply the amount of estrogen that matters.

The rapid swings between high and low levels can create significant symptoms.

Some women are particularly sensitive to these shifts, especially when it comes to mood, sleep, and migraines.

Stress Can Magnify Symptoms

Midlife is often a period of intense responsibility.

Many women are:

• Leading teams and businesses
• Caring for children
• Supporting ageing parents
• Managing relationships
• Navigating major life transitions

Chronic stress can worsen symptoms and make recovery more difficult.

Existing Health Conditions Can Interact With Hormonal Changes

Conditions such as:

• Anxiety
• Depression
• ADHD
• Migraine
• Thyroid disorders
• Autoimmune disease

may become more noticeable or require different management during perimenopause.

Lifestyle Factors Play a Role

Sleep, nutrition, physical activity, alcohol consumption, smoking, and overall health all influence symptom severity and resilience.

Lifestyle alone does not cause or cure perimenopause, but it can significantly affect how symptoms are experienced.

The Most Important Thing to Know

Perimenopause is not “just getting older.”

It is a complex biological transition involving significant hormonal communication between the ovaries, brain, and body.

The symptoms are real.

The impact can be profound.

And there is no single “correct” perimenopause experience.

Some women primarily struggle with anxiety.

Others experience disrupted sleep, heavy periods, hot flushes, brain fog, joint pain, or a combination of many symptoms at once.

A Compassionate Reframe

Many women spend years wondering what is wrong with them before realising they are in perimenopause.

The truth is that you are not failing, becoming less capable, or imagining your symptoms.

Your body is navigating a major hormonal transition.

Understanding what is happening is often the first step toward feeling more informed, empowered, and in control.

Perimenopause is not an ending.

It is a transition.

And while every journey is different, no woman should have to navigate it without knowledge, support, and compassionate care.

mySysters is an app for women in perimenopause and menopause. It was created by Cindy Moy Carr when she needed a symptom tracker for perimenopause and found there were none. She created one for herself, her sister and their friends. Hence, mySysters. Good Housekeeping and Woman’s Day named mySysters the Best App for Women in Perimenopause and a Must Have App for Women.