Hot Flashes

Hot flashes have become known as the hallmark of menopause, although they are far from universal. Only about 50% of postmenopausal women have hot flashes, and only about 15% have severe ones. Most women have hot flashes for about two years; few have them for more than six years.

Hot flashes seem to be the result of fluctuating estrogen levels

Hot flashes are bursts of heat that may begin at a particular point, such as the nape of the neck, and radiate throughout the upper body. Or the whole body may get hot at once. Perspiration, flushing, and heart palpitations often accompany the feeling of heat. A variant of hot flashes—night sweats—can disrupt sleep.

Hot flashes seem to be the result of fluctuating estrogen levels and probably occur during estrogen valleys rather than peaks. Although we think of hot flashes as heat surges, they are actually the body’s attempt to cool off. Blood vessels dilate and the heart races to pump more blood to reach the surface of the body where it’s cooler—an effect that can produce a blush or flush. Sweating is another attempt to bring the body’s temperature down. Hot flashes are often triggered by external factors, such as alcohol, caffeine, and hot foods or beverages. They may also be stimulated by emotional upsets.

There are a variety of ways to treat hot flashes.

Menopausal Hormone Therapy

In July 2002, everything many doctors thought they knew about menopausal hormone therapy (called hormone replacement therapy (HRT) at the time) was called into question when researchers announced that they were stopping the Women’s Health Initiative (WHI), a large randomized placebo-controlled study designed to measure the benefits and risks of menopausal hormone therapy. The study was stopped because an interim data analysis indicated that the risks of this therapy outweighed any benefits the drugs had to offer.

Estrogen was first approved by the FDA to treat menopausal symptoms in 1942. In the mid-1970s, progestin was added to estrogen after studies found that giving women estrogen alone increased the risk of uterine cancer. By the 1990s, the combination of estrogen and progestin, which had become known as hormone replacement therapy, had become the second most frequently prescribed medication in the US. It was widely marketed as a drug that would not only prevent hot flashes but also keep postmenopausal women healthier as they aged.

Now, due to the WHI, we are aware that taking estrogen does not keep women healthy. More than 16,000 women between the ages of 50–79 were enrolled in the WHI trial. Half of the women were given menopausal hormone therapy; half of women were given a placebo. To ensure women’s safety during the trial, the researchers had established an independent data and safety monitoring board (DSMB) to review interim results semiannually. During the tenth analysis, on May 31, 2002, the DSMB found an increased risk for breast cancer, coronary heart disease, stroke, and blood clots that outweighed the benefit of reduced fractures or colon cancer risk. This finding led the DSMB to recommend that the trial be stopped. Today, it is not recommended that women who have or have had breast cancer take menopausal hormone therapy.

How big of a risk did the study find? If 10,000 women were taking menopausal hormone therapy for a year and 10,000 women were not, there would be eight more women in the menopausal hormone therapy group who would develop invasive breast cancer, seven more who would develop heart disease, eight more who would have a stroke, and eight more who would develop blood clots. There would also be six fewer colorectal cancers and five fewer hip fractures.

The WHI trial began around the same time that Wyeth, the drug company that makes the leading HRT drug Prempro, began a randomized, controlled trial called the Heart and Estrogen/Progestin Replacement Study (HERS). This trial included about 2,700 women; half were given Prempro while the other half received a placebo. Findings from the HERS trial, published on July 3, 2002, in the Journal of the American Medical Association, indicated that menopausal hormone therapy did not prevent heart attacks in older women with heart disease and that it increased blood clots and gallbladder disease. This confirmed previous findings from the HERS trial that had been published in 1998.

It is now clear that menopausal hormone therapy is not the women’s wonder drug that many thought it would be. We now know that menopausal hormones:

  • If used for more than five years, increase the risk for invasive breast cancer.
  • Increase the risk for heart attacks, strokes, and blood clots.
  • Increase the rate of incontinence and uterine prolapse.
  • Don’t appear to prevent heart disease.
  • Have not been proven to prevent Alzheimer’s disease.
  • Does not improve quality of life in women who do not have menopausal symptoms.

As a result, it is now recommended that only a low dose of menopausal hormone therapy be used. Several studies have shown that low-dose hormone therapy (.3mg or .15mg of Premarin, Menest, Estratab, Ogen, Ortho-Est, or Cenestin) combined with a daily supplement of 1,000mg of calcium maintains bone density as well as high-dose HRT.

Women should stay on hormones for as short a time as is possible—at most three to five years—to help with menopausal symptoms, like severe hot flashes, night sweats, or vaginal dryness, and then begin tapering off. Women who begin taking hormones in their 30s and 40s following an oophorectomy should begin tapering off in their early 50s.

We currently don’t know if one form of estrogen is better than any other. If one type of hormone therapy is not working for you, you may want to try another. The steadfast rule is that any woman who has a uterus must take an estrogen and a progesterone. (Progesterone was added to decrease the risk of uterine cancer.) Women who do not have a uterus can take only estrogen. In addition to pills, several patches are now available that deliver micronized estradiol. The estrogen passes through the skin into the blood without being broken down in the digestive system (as a pill would be).

Bioidentical Hormones: Are They Better?

After concerns began to be raised about the dangers of menopausal hormone therapy, some women and their doctors began to tout the benefits of bioidentical hormones. Practitioners who use these drugs and the compounding pharmacies that make them claim that bioidentical hormones are better because they are made with natural, rather than synthetic, hormones that are better absorbed by the body. They also claim that because these hormones are similar to those a woman produces, side effects are less likely to occur. Is this true?

Bioidentical hormones are plant-derived; they are made from concentrated soy and yam. So, yes, they are natural in that they are produced by nature. But that doesn’t necessarily mean they are better than the drugs made by pharmaceutical companies. In fact, Premarin (estrogen alone) and Prempro (a combination of estrogen and progestin) contain estrogen that comes from pregnant mares’ urine. That is certainly natural. (Whether it is right is another question. PETA and other animal rights activists are opposed to the practice.)

But just because something is “natural” does not mean it’s safe. Currently, only a handful of small studies have been conducted on compounded bioidentical hormones. They indicate that these drugs are effective. But that does not mean they are safe, or safer than other types of HRT. Not one large randomized trial—the gold standard of medical research—has been conducted with bioidentical hormones. And there have been no randomized trials comparing bioidentical hormones to a drug like Prempro.

Practitioners who recommend bioidentical hormones give women prescriptions to be filled by pharmacies that have the ability to “compound,” or make, individualized doses. Typically, the practitioner determines which hormone to use and at what strength by conducting hormone tests on a woman’s blood or saliva. There is currently no evidence to support these methods as a means of determining what levels of hormones a woman’s individualized menopausal hormones cocktail should be comprised of.

The real benefit of the bio-identical movement is that it has spearheaded a move away from the one-size-fits-all approach of recommending menopausal hormones to all women as they enter menopause. If you prefer using a product that is plant-derived rather than animal-derived, then they might be a good option for you. But there is no indication that these drugs are safer than other forms of menopausal hormones, and you should not stay on them for more than three to five years.

Going Off Menopausal Hormone Therapy

As women who have been diagnosed with breast cancer know firsthand, it is possible—and from a medical perspective, perfectly okay—to stop hormones cold turkey. In fact, about half of all women who stop taking hormones cold turkey will do just fine. The other half will find that the menopausal symptoms that led them to take hormones in the first place come back with a vengeance. This is because stopping hormones turns on the menopausal switch, and that is likely to result in the side effects that women typically go on menopausal hormones to avoid—hot flashes, vaginal dryness, and sleep problems.

Since there is no way to predict which women will experience symptoms and which women won’t when they go off menopausal hormones, every woman must determine which method of going off menopausal hormones is right for her. One option is to taper off menopausal hormones gradually, which allows the body to adjust to decreasing doses of hormones and helps to reduce side effects. The second option is to quit cold turkey and then see if you are one of the lucky ones who don’t have symptoms. If you are in the lucky 50%, you can throw your menopausal hormones away. If you’re not, you can go back on and then begin tapering off gradually.

If you take combination menopausal hormones, which has estrogen and progesterone in the same pill, to begin tapering off you should ask your doctor for two separate prescriptions. This will allow you to better control the dose of each aspect of your menopausal hormones as you taper off. As you taper off, you should also begin taking a daily supplement of 1,000mg of calcium. Once you have tapered off completely, you should take a daily supplement of 1,200mg of calcium along with 400¬–800 IU of vitamin D.

If you are taking standard menopausal hormones, the best way to begin tapering off is to start taking low-dose menopausal hormones—0.3mg (.5mg of Estrace). If you have symptoms on the lower dose, you will need to raise your dose and decrease it more gradually. You can do this by alternating low- and high-dose pills (Monday = high dose, Tuesday = low dose, Wednesday = high dose, Thursday = low dose, etc.) for three to six months before trying to take only the low-dose pills.

A second option is to take the high-dose pills Monday through Friday and not take any pills on the weekends. After you have done this for three to six months, you can then try the low-dose pills again. The only way to know when you can fully drop down to the low dose is by trying it and then seeing if symptoms develop. If they do, and are unbearable, you will need to go back to the routine you were on and taper more gradually. If you are alternating a high-dose pill with a low-dose pill, you can do this by replacing one of the days you are taking a high-dose pill with a low-dose pill (Monday = high dose, Tuesday = low dose, Wednesday = low dose instead of high dose, Thursday = low dose, etc.). Once you have done this for a few months, then try adding in another low-dose day.

If you are taking menopausal hormones Monday through Friday and skipping weekends, try skipping another day, like Wednesday. Then, after a few months, you can try skipping another day. In general, the rule to follow is to go as slowly as you need to and to not go to the next reduction until symptoms that may have developed are easy to handle.

After a few months on the lower dose, you have two options: You can discontinue estrogen altogether or you can continue to take a smaller amount by cutting your pills first in half and taking a half dosage for a few weeks, and then cutting the pills in quarters and taking a quarter dose for a few weeks. Another option is to take a low-dose pill every other day.

If you are currently taking a higher dose of menopausal hormones—1.25mg (2mg Estrace)—you should begin tapering by dropping down to the standard dose—.635mg (1mg Estrace). You should continue to take the progesterone until you taper down to the low-dose level—0.3mg (0.5mg of Estrace). Once you are at the lower dose, you can discuss with your clinician whether to remain on the progesterone while you finish tapering off.

Money tip: menopausal hormones costs the same regardless of the dosage you are prescribed. To help reduce your costs you may want to keep your prescription dosage the same, but cut your pills in half.

Alternatives to HRT: Prescription Options

Not all women want to take hormone replacement therapy (HRT), and women who have had breast cancer or are at high risk for breast cancer are not advised to do so, due to fears it will increase the risk of cancer or a recurrence. What options are available to these women?

Prescription options for treating hot flashes include antidepressants, gabapentin, and clonidine.


Studies have found that the antidepressant venlafaxine (brand name Effexor) decreased hot flashes by 50%. Studies of two SSRIs (selective serotonin reuptake inhibitors), fluoxetine (brand name Prozac) and paroxetine (brand name Paxil), found that these also reduced hot flashes by 50% when compared to placebo. That means if you have six hot flashes a day, taking an SSRI may reduce this to three. If your hot flashes are bad, these drugs may be worth a try. Because each drug works slightly differently, if one doesn’t work, you may want to try another before giving up on all of them.

Antidepressants might be especially helpful to women whose symptoms include both hot flashes and depression. SSRIs are believed to work because of the role serotonin plays in regulating the body’s temperature. When used to treat hot flashes, these drugs are prescribed at half of the daily dose that would be used to treat depression. This is done to try to decrease SSRI-associated side effects, such as dry mouth, nausea, appetite change, and decreased libido.


Gabapentin (brand name Neurontin) is another drug that may have found a home as a treatment for hot flashes. It’s typically used to treat migraines, but when women using it for that purpose found it also stopped their hot flashes, researchers began to study the drug more closely.

In September 2005, results from a study conducted at the University of Rochester of 420 women with breast cancer who were having two or more hot flashes a day were published in Lancet. The study, which randomized women to two different doses of gabapentin or to a placebo, found that 900mg of gabapentin reduced hot flashes by about half. (A dose of 300mg/day was not effective.) That means if you had four hot flashes a day, you would now have two. Although the study was conducted in women with breast cancer, there is no reason to believe these findings are limited to that group, making the drug an option for all women in need of symptom relief.


Clonidine (brand name Catapres) is normally used to control blood pressure, but it is now sometimes recommended for women who experience hot flashes while on tamoxifen, a hormone used to treat breast cancer. In an eight-week placebo-controlled trial in postmenopausal women with tamoxifen-induced hot flashes, 38% of the women on clonidine reported a reduction in hot flash frequency compared with 24% of the women on placebo. However, there were a lot of side effects: fatigue, nausea, irritability, headache, and dizziness. So, while this drug may be an option for some women, the side effects may be a huge drawback for others.


In May 2006, the Journal of the American Medical Association published “Nonhormonal Therapies for Menopausal Hot Flashes.” This paper is a review and assessment of the previously published studies on the use of antidepressants, gabapentin, and clonidine for treating hot flashes. The authors concluded that these drugs are less effective than estrogen in reducing hot flashes and that “these therapies may be most useful for highly symptomatic women who cannot take estrogen but are not optimal choices for most women.”

In an accompanying editorial, Jeffrey A. Tice, MD, and Deborah Grady, MD, of the University of California, San Francisco, discuss the research findings. They note, “Women with hot flashes should understand that most symptoms resolve over several months to several years … For women with more bothersome symptoms, clinicians should understand the advantages and disadvantages of both hormone therapy and nonhormonal alternatives. Hormone therapy is more effective than nonhormonal alternatives but should probably be avoided by women at high risk for venous thromboembolic events [blood clots], cardiovascular disease, and breast cancer.”

Alternatives to HRT: Lifestyle Options

Not all women want to take hormone replacement therapy (HRT), and women who have had breast cancer or are at high risk for breast cancer are not advised to do so, due to fears it will increase the risk of cancer or a recurrence.

The other option is to try to avoid hot flash triggers like spicy foods, caffeine, stressful situations, and hot drinks. You may also want to try sleeping in a cool room; carrying a hand fan; dressing in cotton and in layers; or paced respiration exercises (deep, slow abdominal breathing).

Here are some other things you can do on a day-to-day basis to help alleviate hot flashes—or at least make them easier to bear:

  • Keep the heat turned down, especially in the bedroom at night.
  • Dress in layers that can be easily shed when your temperature rises.
  • Wear exercise clothing that wicks away sweat during the day and at night.
  • Exercise regularly.
  • Learn and practice stress reduction.
  • Learn and practice paced respiration. Paced respiration is breathing from deep inside your abdomen, while slowing your breaths to five to six times a minute (normal is 10–15 breaths per minute). You practice breathing in for five seconds and breathing out for five seconds to get the timing right. Practice every day for 15 minutes. Then, if you feel a hot flash coming on, try decreasing your breathing, which may help nip that hot flash in the bud.

    Alternatives to HRT: Complementary Care

  • Not all women want to take hormone replacement therapy (HRT), and women who have had breast cancer or are at high risk for breast cancer are not advised to do so, due to fears it will increase the risk of cancer or a recurrence.

    Complementary care options include acupuncture; eating a serving of soy foods and ground flaxseeds daily; or walking, swimming, dancing, or bike riding every day for 30 minutes or more. You can also try vitamin E (800mg) or the herb black cohosh. If nothing helps alleviate your symptoms, you may want to join or create a support group to help you deal with them.

    The following herbs, supplements, and complementary care practices may help alleviate hot flashes in some women.


Acupuncture is designed to influence the body’s life force, which is known as “qi” or “chi” (pronounced chee). According to acupuncture principles, chi flows through the body along paths called meridians. By twirling hair-thin needles inserted at specific points along meridians, each of which is associated with a particular physical problem, acupuncture seeks to correct imbalances.

Acupuncture has been gaining an increased role in Western medicine, first in Europe, then in the United States. In 1997, the National Institutes of Health acknowledged that acupuncture is effective in treating certain conditions. Although hot flashes weren’t among those listed, there is some evidence from studies conducted in Europe that it is effective. In one Swedish study, women who underwent acupuncture therapy had relief from hot flashes that lasted several months.

If you decide to try acupuncture, you should be sure to see a licensed acupuncturist. You may also want to check to see if your health insurance covers acupuncture as part of its alternative and complementary medicine coverage.

Black Cohosh

Black cohosh is an herb that has long been used by Native Americans to treat menstrual and menopausal symptoms, but its mechanism is not understood. More recently it has become popular in the United States as a suggested treatment for hot flashes. A study of Remifemin Menopause, made from an extract of black cohosh, found that 70% of the 150 peri-and postmenopausal women in the study who took 40mg of Remifemin for 12 weeks reported a decrease in menopausal symptoms, including hot flashes. The group taking the higher dose did not do better than the lower standard-dose group. There was no placebo group in this study to compare the response with.

Black cohosh may be a good option for some women. The advantage of it over other alternatives is that it doesn’t have side effects, like clonidine and antidepressants. But it’s also clear that more is not better, and that women who do decide to try it should stick to the standard dose.

The question for breast cancer survivors is whether it is estrogenic. On this front we actually have some data. First of all there is no known phytoestrogen in black cohosh. Second, there is no evidence that black cohosh binds to the estrogen receptor. Finally, in a petri dish, breast cancer cells were exposed to black cohosh in the absence of estrogen, in the presence of estrogen, and in the presence of tamoxifen. They found that the black cohosh given alone inhibited cell growth. When estrogen was added it blunted the growth usually seen and it enhanced the effects of tamoxifen. This effect has been replicated in four other studies on cell lines. Studies in women have confirmed this lack of estrogenic effect.

Red Clover

Another commonly used herb, red clover, contains the daidzein and genistein found in soy as well as formononetin and biochanin. It is marketed for hot flashes and menopausal symptoms. There have been two randomized controlled studies comparing it to placebo. Neither study found that red clover was better than the placebo. There is concern about its ability to stimulate breast cancer, but this has not been studied. In addition, red clover produces dicumarol, which can block blood clotting.


Soy is a food source of isoflavones. Sometimes it is called a phytoestrogen. This is a poor word choice. Although soy acts like estrogen in some organs, it blocks estrogen in others—so it’s more like a phytoSERM (selective estrogen receptor modulator) than a pure estrogen. There have been several randomized controlled studies on hot flashes and soy, showing a reduction in hot flashes not only in countries where soy is a large part of the diet, like China and Japan, but also in the West. But there are other studies that didn’t show that soy was effective at all. In addition, soy not only decreases LDL cholesterol (the bad kind), but also increases the good cholesterol, HDL, significantly. And unlike Premarin, which increases triglycerides, soy decreases them. It also increases bone density.

Some women who have had breast cancer report that they are worried about eating soy because it might fuel their ER-positive tumors. There is no evidence that eating small amounts of soy is a problem. But if this concerns you, just don’t eat it.

Additional Resources:

You can learn more about what is known about these and other herbs and supplements on these websites:

Information specific to cancer survivors is available on these sites:

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