HRT for Hot Flashes: How to Reset Your Body’s Internal Thermostat
When bursts of heat strike, hormone replacement therapy could be the best way to cool down
Hot flashes—whether mild bursts that pass when you remove a layer or engulfing flames that leave you drenched and wide-eyed at 2 a.m.—are one of the most common symptoms of menopause. They affect up to 80 percent of women in the menopause transition, and they can be traced back to the primary driver of most menopause symptoms: a drop in estrogen. 1 Hormone replacement therapy (HRT) supplements your body’s natural estrogen production, helping to recalibrate your internal thermostat to reduce hot flashes by up to 75 percent. 2
In fact, HRT (also called menopause hormone therapy or MHT), is considered the gold standard treatment for vasomotor symptoms like hot flashes. 3 And research published in 2024 in JAMA confirms that for most women who start HRT before the age of 60, the benefits outweigh the risks. 4
If hot flashes are disrupting your sleep, focus, or day-to-day rhythm during menopause, here’s why HRT is worth a conversation with your doctor.
About the Experts
Natalie Kunsman, M.D., M.S., is a board-certified family physician and integrative medicine physician who treats women in menopause.
Marilyn Lajoie, M.D., is an internal medicine physician and expert in hormone therapy.
Benefits of HRT for Hot Flashes
Hot flashes happen when estrogen and progesterone levels drop, making the brain’s thermostat (your hypothalamus) more reactive to tiny shifts in temperature. HRT replaces these lost sex hormones to help calm this system down. It also improves sleep (insomnia is linked to hot flashes) and lowers stress hormones that can make vasomotor symptoms worse.
HRT regulates the body’s thermostat
Taking HRT containing estradiol for hot flashes calms the brain’s temperature control center, preventing overreactions to small changes in body temperature.
The hypothalamus in your brain acts as your body’s internal thermostat. When estrogen levels decline in menopause, it becomes more sensitive to tiny temperature changes, explains integrative physician Natalie Kunsman, M.D. The culprit: KNDy neurons, cells in the hypothalamus that help regulate reproductive hormones, and when deprived of them, become overstimulated.
Even a slight rise in body temperature—from spicy food, a warm room, or stress—can trigger a hot flash when estrogen is low. 5 “Your blood vessels dilate to dump heat, which causes a sudden rush of heat to the skin,” Kunsman says. It’s an exaggerated reaction, like using a swimming pool full of water to put out a candle.
Replacing estrogen with HRT calms the KNDy neurons and prevents the hypothalamus from unnecessarily triggering vasodilation. Micronized progesterone, a hormone taken with estrogen in many HRT regimens (particularly for women with a uterus), may provide extra support by further stabilizing the temperature regulation system. 6
HRT supports better sleep and decreases night sweats
Menopause wrecks sleep for 40 to 60 percent of women, and night sweats are a big reason why. HRT helps improve sleep by reducing night sweats and promoting deeper, more restful sleep.
Research shows that estrogen replacement therapy helps menopausal women fall asleep faster, improves sleep quality, and decreases middle-of-the-night awakenings (after all, it’s hard to sleep when you’re sweating and overheated from a hot flash). 7 Progesterone can enhance these effects by promoting relaxation and reducing anxiety, making it easier to get the deep, restorative sleep you need.
HRT may reduce stress hormones
Research on HRT and cortisol is mixed, but some studies suggest hormone therapy helps regulate stress by lowering cortisol, a stress hormone that plays a role in temperature regulation. 8
Hormone changes, poor sleep, and ongoing stress in menopause can raise cortisol, which. activates the sympathetic nervous system and increases body temperature. And some research has found evidence that higher cortisol levels have been associated with more severe hot flashes. 9
“Estrogen helps lower cortisol by calming the nervous system,” says Kunsman. It also boosts serotonin, a hormone and chemical messenger that’s involved in regulating mood, as well as gamma-aminobutyric acid, an amino acid that promotes relaxation and helps manage anxiety, she adds.
However, the research on HRT’s impacts on cortisol (and therefore hot flashes) is still emerging, and more studies are needed.
Types of HRT for Hot Flashes
Estradiol patches and pills tend to alleviate menopause hot flashes most effectively, says Kunsman. This is because they are systemic—meaning they travel through the bloodstream to work throughout the body. “We reserve pills for cases where there is intolerance to or irritation with patches, because of their higher risk of side effects like blood clots, stroke, and high blood pressure,” Kunsman says.
Localized estrogen treatments like vaginal rings and vaginal estrogen cream are typically used for vaginal symptoms, and may not deliver enough hormone to relieve hot flashes unless the dose is high.
Estradiol patch for hot flashes
The estradiol patch delivers a steady dose of estrogen into the bloodstream via your skin to reduce the hormone fluctuations that contribute to hot flashes. You apply it to your lower belly or upper buttocks, and change it out as prescribed by your physician (typically from twice a week to once every two weeks).
Estradiol vaginal rings
This soft, flexible ring is inserted into the vagina where it steadily releases a low dose of estradiol for three months.
“Lower doses, like 0.0075 mg a day, help vaginal dryness but not hot flashes,” says Kunsman. You’d need to use a higher-dose ring—one that delivers 0.05 to 0.1 mg per day—to raise blood estrogen levels enough for full-body benefits and hot flash relief. 10
In one small study, high-dose estradiol vaginal rings (0.06 mg and 0.14 mg) led to an 80 percent reduction in hot flashes in women who’d gone into menopause after having a hysterectomy. 11
Estrogen cream for hot flashes
Topical estrogen creams and gels only treat hot flashes when the dose is high enough to raise estrogen levels throughout your body.
Higher-dose estradiol gel or cream, applied daily to your arm or thigh, delivers estrogen through the skin into your bloodstream. Unlike vaginal estrogen cream, the dose here is high enough to have a systemic effect, which helps reduce the frequency and severity of hot flashes.
Vaginal estrogen cream works locally to target dryness, pain, and recurring UTIs; the dose isn’t high enough to raise overall estrogen levels, so it won’t help relieve hot flashes.
Progesterone for hot flashes
Some research suggests that micronized oral progesterone can also help with hot flashes, though to a lesser degree than estrogen replacement.
A randomized-controlled trial that followed almost 200 women in perimenopause found that progesterone was no better than a placebo at reducing hot flash frequency, as measured in a daily diary. But when women were given a perceived change questionnaire to indicate how they felt their night sweats had changed, those who were prescribed progesterone felt like the treatment significantly decreased their night sweats, hot flash intensity, and the effects of these symptoms on their lives. 12
Another study found that 300 mg of oral micronized progesterone taken at bedtime effectively relieved hot flashes and night sweats in postmenopausal women. 13
Usually, progesterone is added to estrogen in women who still have a uterus to reduce their risk of uterine cancer. But some women who’ve had a hysterectomy may still benefit from progesterone for hot flashes and sleep.
| Hormone Therapy Type | Helps Hot Flashes? |
| Estradiol patch | Yes |
| Estradiol vaginal rings | Only in higher doses |
| Vaginal estrogen | No. Only eases vaginal symptoms (dryness, itching, painful sex, UTIs) |
| Higher dose estradiol gel or cream | Yes |
| Micronized progesterone pills | Yes, but to a lesser degree than estradiol |
How Long Does It Take Estradiol to Work for Hot Flashes?
Estradiol delivered through a patch, pill, or transdermal cream or gel can start to reduce the frequency and severity of hot flashes within 1 to 2 weeks. However, some women don’t get full relief for 1 to 2 months, Kunsman says.
Is HRT Safe for Treating Hot Flashes?
Major medical groups and menopause organizations agree that for the majority of women, HRT is a safe and effective way to treat hot flashes. Menopause Society guidelines say that for women ages 60 or younger who started menopause less than 10 years before, the benefits of HRT for treating vasomotor symptoms outweigh the risks. 14
Concerns about HRT’s safety date back to the 2002 Women’s Health Initiative (WHI) study, which linked HRT to increased risks of breast cancer, stroke, and heart disease. 15 However, many studies since then have clarified the risks and reaffirmed the safety of HRT.
A 2024 review in JAMA, confirmed that while HRT isn’t recommended for preventing chronic disease, it is effective and safe for treating vasomotor symptoms like hot flashes in women who are in early menopause. 16 Some women may safely be able to stay on HRT if their hot flashes persist.
What to Know About Starting Estrogen for Hot Flashes
The best time to start HRT is within 10 years after you enter menopause, and ideally before age 60, says Kunsman. Use the lowest dose of estrogen needed to relieve hot flashes and schedule yearly follow-up appointments with your doctor to make sure the treatment is still working for you.
Here are some things to expect when you start taking HRT for hot flashes.
Taking estrogen can cause hot flashes at first
While HRT is meant to relieve hot flashes, it’s not unusual for symptoms to temporarily worsen as your body adjusts. This typically improves within a few weeks.
What if you’re still getting hot flashes with HRT?
If you’re having hot flashes several weeks after starting HRT, check back with your provider. You may need to adjust the delivery method or timing of your doses, or add progesterone, Kunsman says.
The Bottom Line
Estrogen replacement therapy is the most effective way to relieve hot flashes and other vasomotor symptoms during menopause. Delivery methods like the patch work better for hot flashes than local treatments like the vaginal cream and ring. HRT is safe for most younger women who start HRT within 10 years of menopause onset.
The Menopause Society (n.d.) Hot Flashes
↑Cameron CR, et al. (2024.) The Art of Hormone Replacement Therapy (HRT) in Menopause Management
↑Lugo T, Tetrokalashvili M. (updated 2022) Hot Flashes.
↑Manson JE, Crandall CJ, Rossouw JE, et al. (2024) The Women’s Health Initiative Randomized Trials and Clinical Practice: A Review.
↑Szeliga, A. et. al. (2018) The role of kisspeptin/neurokinin B/dynorphin neurons in pathomechanism of vasomotor symptoms in postmenopausal women: from physiology to potential therapeutic applications
↑Prior, Jerilynn, C, et al. (2023.) Oral Micronized Progesterone for Perimenopausal Night Sweats and Hot Flushes: A Phase III Canada-Wide Randomized Placebo-Controlled 4 Month Trial
↑Clintron, Dahima, et al. (2017.) Efficacy of Menopausal Hormone Therapy on Sleep Quality: Systematic Review and Meta-Analysis
↑Tan Q (2023) Thermoregulatory Hormones: Endocrinology of Body Temperature Regulation.
↑Woods NF, Mitchell ES, Smith-DiJulio K. (2009) Cortisol levels during the menopausal transition and early postmenopause: observations from the Seattle Midlife Women’s Health Study.
↑Cohn AY, et al (2023). Effects of Sleep Fragmentation and Estradiol Decline on Cortisol in a Human Experimental Model of Menopause.
↑FDA. (2020.) Highlights of Prescribing Information: Femring
↑Nash HA, et al (1999.) Estradiol-Delivering Vaginal Rings for Hormone Replacement Therapy
↑Prior, J.C., Cameron, A., Fung, M. et al. (2023) Oral micronized progesterone for perimenopausal night sweats and hot flushes a Phase III Canada-wide randomized placebo-controlled 4 month trial.
↑Hitchcock CL, Prior JC. (2012.) Oral Micronized Progesterone for Vasomotor Symptoms – a Placebo-Controlled Randomized Trial in Healthy Postmenopausal Women
↑NAMS (2022) The 2022 hormone therapy position statement of The North American Menopause Society
↑Harper-Harrison G, Carlson K, Shanahan MM. (updated 2024) Hormone Replacement Therapy.
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About the author
Stephanie Watson is a freelance writer whose work has appeared in WebMD, Time, Forbes Health, Fortune Well, Greatist, Healthgrades, Healthline, HealthCentral, and many other leading health publications. Previously, she was the executive editor of Harvard Women’s Health Watch and Mount Sinai’s Focus on Healthy Aging.
About the reviewer
Dr. Kimberly Hood is a board-certified OB/GYN and functional medicine provider specializing in men's and women's hormone health, weight management, longevity, thyroid health, and sexual wellness.
