When Does Menopause Actually Start?

Like Mercury retrograde, menopause is blamed for a constellation of unpleasant or inexplicable events. Women in their forties or even younger hold menopause responsible when they experience a wide array of physical symptoms, like irregular periods, aches and pains, mood swings, weight gain, insomnia, fatigue, and bursts of hunger—but they may be misattributing these annoyances. It turns out that many women don’t know when menopause actually starts.

According to a February 2025 poll of 1068 women by The Ohio State University, 61 percent of respondents believed they’ll hit menopause in their forties. And while some will, the National Institute on Aging reports the average age of menopause onset is actually 52, though it can be hard to tell where the dividing line is.

1. Perimenopause vs. Menopause
2. Menopause: Still a Medical Mystery

Perimenopause vs. Menopause

Some women may mistake perimenopause symptoms for menopause itself. The medical definition of perimenopause is when your period is irregular by at least seven days for a minimum of 10 months—so when that happens (and if you’re keeping track), you know you’ve started perimenopause. Menopause itself, defined as the point in a woman’s life when her period permanently stops, hasn’t actually started until 12 full months have passed without menstruation occurring.

Perimenopause (peri- means “near” or “around”) is the phase when your body begins to prepare for menopause. Your hormone levels start to fluctuate, causing mood swings, hot flashes, problems sleeping, and irregular periods. It usually begins when you’re in your mid-forties and lasts for eight to 10 years before menopause starts in your early fifties, according to the Cleveland Clinic.

That being said, the age when menopause starts can really fluctuate from person to person. A study from the Turkish Journal of Obstetrics and Gynecology found that health, socioeconomic, and hereditary factors can affect its timing. Some of those factors include your mother’s age when she hit menopause, the age you got your first period, how long you were in your mother’s womb, whether you used birth control pills, the stability of your cycle before perimenopause, how many children you have, your weight, use of cigarettes and alcohol, the amount of physical activity you get, education level, socioeconomic status, if you’ve had an ovary removed, the amount of lead in your blood, how much fat you eat, and more. 

Menopause: Still a Medical Mystery

Ultimately, we may never be able to pinpoint an exact age that perimenopause and menopause begin, thanks to all of those factors. Plus, women’s healthcare—especially menopause—remains under-researched even though menopause affects 100 percent of 50 percent of the population. 

According to findings from Harvard Medical School, 99 percent of preclinical models of aging don’t take the effects of menopause into account, meaning that these guidelines for treating age-related conditions don’t reflect reality. That’s partially because scientists lack the proper lab animals for menopause studies, such as female animals and those that have given birth. Most studies use male animals, and historical research overwhelmingly favors men. Additionally, menopause is quite rare in the animal world—only a few mammals, including chimpanzees and killer whales, are known to go through it.

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