What causes hot flashes during perimenopause?

Hot flashes happen because declining estrogen triggers a specific cluster of neurons in the hypothalamus, your brain's thermostat, to become overactive. These neurons, called KNDy neurons, project into the areas of the brain that control heat regulation and, when activated, set off a cascade that includes flushing, sweating, and a sudden intense sensation of heat. Hot flashes are not imagined and they are not random. They are a measurable physiological response to real hormonal change. They affect up to 80 percent of women at some point in the menopause transition, making them the most common perimenopausal symptom.

Always consult your healthcare provider before starting any new supplement, especially during perimenopause or while managing a medical condition.

The brain mechanism behind a hot flash

A review published in PMC describes the physiology precisely: KNDy (kisspeptin-neurokinin B-dynorphin) neurons in the arcuate nucleus of the hypothalamus become hyperactive when estradiol levels decline. These neurons project to thermoregulatory areas in the hypothalamic preoptic area, where they trigger heat-loss mechanisms, including skin flushing and sweating. That is what a hot flash is from the inside: the body executing a heat-dissipation response it does not actually need, because the hypothalamic "thermostat" has been thrown off by the loss of estrogen's moderating influence.

Norepinephrine and serotonin also play a role, which is one reason stress, caffeine, alcohol, and warm environments can trigger or intensify hot flashes. The National Center for Biotechnology Information notes that norepinephrine metabolites in the blood rise both before and during a hot flash, meaning the body's stress signaling system is involved in the cascade.

Night sweats are hot flashes that occur during sleep. Research published in PubMed found that hot flashes occurring in the two hours before sleep onset were associated with measurable disruptions to sleep architecture. This is why night sweats are not just a discomfort issue. They have downstream effects on energy, mood, and cognitive function the next day.

Why hot flashes vary so much between women

Not every woman experiences hot flashes the same way. Frequency can range from a few per week to dozens per day. Intensity varies from mild warmth to drenching sweats. Duration varies from months to years. A large international study led by Mayo Clinic found that while hot flashes were the most widely recognized symptom of perimenopause, fatigue and irritability were actually the most common reported experiences in the 35 and older age group, suggesting that hot flashes are often preceded by other shifts in how women feel.

Stress level, sleep quality, body composition, and individual hormonal patterns all influence how hot flashes present. This is one reason a whole-body approach to perimenopause support is more effective than any single intervention.

The stress and hot flash connection

The nervous system overlap between the stress response and thermoregulation means that high-stress periods tend to correlate with more frequent or more intense hot flashes. Supporting a healthy stress response is a practical way to ease one of the triggers within your control.

Research across multiple randomized controlled trials, compiled in a 2024 meta-analysis published in Explore: The Journal of Science and Healing, found that ashwagandha supplementation was associated with meaningful improvements in perceived stress and anxiety compared to placebo. Research suggests that reducing the body's stress burden may support more comfortable navigation of vasomotor symptoms.† Pink Stork Cortisol Complex, a daily adaptogen blend for stress support, includes 300 mg of organic ashwagandha root alongside algae-sourced DHA, chamomile, and a full B-vitamin complex.†

Sleep, NAD+, and the energy cost of hot flashes

Hot flashes disrupt sleep. Disrupted sleep depletes cellular energy. And cellular energy, specifically in the form of NAD+, declines with age, potentially amplifying the fatigue that perimenopausal women already face. Supporting healthy NAD+ levels addresses the energy layer of this equation.† our 500 mg Nicotinamide Riboside supplement is a once-daily cellular energy formula third-party tested in cGMP-certified laboratories and designed for women navigating midlife transitions.†

"Sleep is… the king, the queen… of health."

— Dr. Samantha Ess, ND, Naturopathic Doctor specializing in hormone health and fertility

Whole-food nutrients and the midlife transition

Nutrient density matters during perimenopause. Whole-food sources of B-vitamins, iron, CoQ10, and selenium support the systems that are working harder during this transition. Beef Organ Complex, a whole-food blend of grass-fed liver, heart, kidney, and female-focused organ powders, is formulated specifically for women navigating hormonal changes and is the first beef organ supplement in its category to earn the Clean Label Project Purity Award.†

Lifestyle approaches with evidence behind them

The NCBI overview of hot flash management notes that while evidence for nonmedicated approaches is still growing, several lifestyle changes are reasonable to consider:

• Layering clothing to manage body temperature throughout the day
• Maintaining a cooler sleep environment
• Reducing caffeine and alcohol intake, both of which can act as vasomotor triggers
• Regular exercise, which supports overall cardiovascular and metabolic health during the transition
• Managing stress through consistent daily practices

For more on the cardiovascular changes that often accompany hot flashes, see what perimenopause does to your heart health. For context on when perimenopause typically begins, see what age does perimenopause start.

"We design every product with the understanding that what you are going through is real, and that you deserve real support. Hot flashes are your body communicating. Our job is to help you listen."

— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

Frequently asked questions

What causes hot flashes during perimenopause?

Declining estrogen causes KNDy neurons in the hypothalamus to become overactive, triggering the body's heat-loss mechanisms without a genuine temperature threat. The result is flushing, sweating, and a sudden intense sensation of heat. Norepinephrine and serotonin signaling are also involved, which is why stress and stimulants can worsen hot flashes.

How long do hot flashes last during perimenopause?

A single hot flash typically lasts one to five minutes. The overall period during which women experience hot flashes can last from a few months to more than a decade. Some women continue experiencing vasomotor symptoms years after reaching menopause.

Do hot flashes happen at night too?

Yes. Night sweats are hot flashes that occur during sleep. Research shows they can disrupt sleep architecture, affecting energy, mood, and cognitive function the following day.

Can stress make hot flashes worse?

Yes. The nervous system pathways involved in the stress response overlap with those involved in thermoregulation. High stress periods are often associated with more frequent or more intense hot flashes. Supporting a healthy stress response is a practical lever within your control.†

Are hot flashes a sign of something serious?

Hot flashes are a normal part of the perimenopause and menopause transition for many women. However, research has also linked the midlife transition to changes in cardiovascular health markers. Discussing all of your perimenopausal symptoms with your healthcare provider is worthwhile, particularly if hot flashes are frequent or severe.

What can help with hot flashes naturally?

Lifestyle approaches including temperature management, caffeine and alcohol reduction, and stress support have reasonable evidence behind them. Certain adaptogens, including ashwagandha, have been studied for their role in supporting a healthy stress response, which may indirectly support comfort during perimenopause.† Always consult your healthcare provider before starting any new supplement.

† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.