Is This Perimenopause?
Reviewed by Liz Riesen, RD, CD. Last reviewed 09/2026.
If your sleep has fallen apart, your periods aren't behaving, and the routines that used to work have stopped working, you may be wondering whether this is perimenopause or something else. You're not imagining it, and you're not alone.
Perimenopause is the transition leading up to menopause. For many women it begins in their 40s, sometimes earlier, and it can last several years. However, we are seeing earlier signs and many women including myself may experience changes in cycle and symptoms as early as 35 years old. It's unclear if this is due to an increase in awareness through social outlets, technology like smartwatches, or due to body burden of stress and toxins. Symptoms often start well before periods stop, and they can look very different from one woman to the next.
In this guide, I'll walk through the most common signs, the other conditions that can look similar, and when it's worth talking to your doctor. If you'd like support with the nutrition side afterward, I'll show you where to start.
What Is Perimenopause?
Perimenopause is the stretch of time when your body begins shifting toward menopause, which is officially reached after 12 months without a period. For most women it starts in their 40s and lasts a number of years, though the timeline varies a lot. I started noticing signs of hormone shifts and cycle changes at 35 years old.
What makes perimenopause so challenging to identify (and frustrating) is that during this time, your hormones don't decline in a simple, smooth line. Instead, estrogen and progesterone can swing higher and lower from month to month, and sometimes from week to week. That's why symptoms can seem to come and go, and why one month can feel very different from the next.
Common Perimenopause Symptoms
Every woman's experience is different, and you may have some of these but not others. In my experience working with women and hormones, there is nothing "common" about perimenopause symptoms, but this is a list of some of the most talked about.
Cycle changes
Periods that are shorter, longer, lighter, heavier, or less predictable
Skipped periods
Sleep and temperature
Night sweats or hot flashes
Trouble falling asleep or waking in the early hours
Mood and thinking
Anxiety, irritability, or mood swings that feel out of proportion
Brain fog, or trouble with focus and word recall
Body changes
Weight that shifts to the midsection, even if your habits haven't changed
Joint aches, headaches, or changes in migraines
Breast tenderness, vaginal dryness, or changes in sex drive
A racing or fluttering heartbeat (worth mentioning to your doctor, see below)
What Can Look Like Perimenopause?
Many of these symptoms can overlap with other causes, which is why it's important to rule out other conditions that can look similar, including:
Thyroid changes, which can cause fatigue, weight changes, mood shifts, and irregular periods. I recommend a full thyroid panel including free T4, free T3, reverse T3 and thyroid antibodies.
Low iron or anemia, which can cause exhaustion, brain fog, and heavy periods. Make sure to get ferritin level drawn which is our body's iron stores, this is a level I often see below optimal range, less than 50 ng/ml
Sleep problems, including sleep apnea, which can mimic fatigue and low mood
Depression or anxiety that isn't hormone-related
PCOS, which can cause irregular cycles and weight changes
Medication effects and high, ongoing stress
Pregnancy, which is easy to overlook when periods become irregular
How is Perimenopause Identified?
For most women in the typical age range, perimenopause is recognized by looking at age, symptoms, and changes in the menstrual cycle, along with ruling out other causes. Your doctor may order labs such as thyroid function, iron levels, or blood sugar to check for those look-alikes.
Since hormone levels can rise and drop sporadically in perimenopause, blood hormone tests generally can't confirm perimenopause on their own.
This is why comprehensive hormone panels can give more insight since they look at wider picture of the hormone picture; including adrenal and stress hormones, melatonin, organic acids (nutrient markers), neurotransmitters, and inflammatory markers. This can help shape nutrition and lifestyle planning, but it isn't a diagnosis of perimenopause.
Learn more about a comprehensive hormone panel here.
When to See Your Doctor
Many perimenopause symptoms are uncomfortable, but not dangerous. Some symptoms, though, deserve a medical evaluation rather than a guess, and I'd rather you get checked than wonder. Talk to your doctor if you notice:
Very heavy bleeding, such as soaking through a pad or tampon every hour for several hours, or passing large clots
Periods that come closer together than every 21 days, or bleeding that lasts longer than 7 days
Bleeding between periods or after sex
Any bleeding after 12 months without a period
Irregular or missing periods before age 40
Symptoms that are affecting your work, relationships, or daily life
Always seek care for chest pain, a racing or irregular heartbeat with shortness of breath, or fainting. Having a team of providers working with you ensures that you get the full support and care that you deserve.
Your Next Step
If you're not sure whether what you're feeling is perimenopause, or you know it is and want a clear plan, I'd be glad to talk it through with you.
Not sure where to start? Tell me what you're noticing, and we'll work out the next step together. No obligation.
Your body isn't broken — symptoms are your body's way of asking for help. It's time to listen.
Most women land here after being told their labs are "normal" or that they just need to lose weight or worry less.
I've been there myself, and I built my practice around what actually helped: real testing, real answers, and a plan built around your body — not a guess.
Liz Riesen, RD
Registered Dietitian
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