An experimental once-a-day pill that works without hormones significantly reduced the number of hot flashes experienced by women going through menopause and improved their sleep compared to a placebo, according to two new trials from drugmaker Bayer.

The drug, called elinzanetant, works by blocking the brain chemicals responsible for hot flashes and night sweats – what doctors call vasomotor symptoms – in women whose ovaries have slowed production of the hormones estrogen and progesterone. This marks a phase of life for women called menopause, which usually happens sometimes in a woman’s 40s or 50s.

The US Food and Drug Administration approved a similar drug called fezolinetant, sold as Veozah, last year.

Such drugs are new options for women during a phase in their lives when their bodies are adjusting to a new hormonal normal. This transition can bring on a wide variety of symptoms including mood swings, brain fog, libido changes and insomnia.

For some women, the symptoms are bothersome but don’t interfere with daily functioning. For others, though, they can be debilitating, and many doctors are reluctant to offer the traditional treatment, hormone replacement therapy, for fear it could increase the risks of stroke, cancer and heart disease.

“Very few women get any sort of help,” said Dr. Stephanie Faubion, who is director of the Mayo Clinic Center for Women’s Health.

At the height of its use in the 1990s, some 40% of postmenopausal women were taking hormone replacement therapy, or HRT, Faubion said. But after a large government study found an increased risk of heart disease and cancer associated with the use of HRT for women, use of hormones for menopausal symptoms fell to around 4%, Faubion said in a commentary about the studies.

Newer studies, including several new analyses of the data from the government trial, have shown that HRT is not tied to increased risks to a woman’s health when it’s used close to the time of menopause and limited in duration, but many doctors remain skeptical.

In addition, survivors of hormone-sensitive cancers, such as some breast cancers, can’t take hormones for menopausal relief. For them, the new non-hormonal drugs are great options, said Faubion, who was not involved in the new studies. Veozah, the drug already approved, is expensive, however. Veozah has a list price of $550 a month, and many insurers are reluctant to pay for it. Bayer, the company that makes elinzanetent, has not said what it would charge for its drug.

Faubion says she’s tried to prescribe Veozah for a few patients but their insurance companies required that they try at least two different, less expensive medications before covering the drug.

“They have to jump through hoops. And I have prescribed it before,” Faubion said. She’s not sure her patients actually took the Veozah. “I don’t know if they actually received the prescription or if they gave up before they got it.”

Both fezolinetant and elinzanetant are among the first drugs to take advantage of a newly understood pathway in the brain that appears to control hot flashes.

As estrogen decreases in menopause, nerves in the hypothalamus — a tiny almond-sized region deep inside the brain that among other functions helps to regulate the body’s thermostat — become hyperactive and produce an overabundance of chemical signals called neurokinins. Both new drugs block the doorways on cells where certain neurokinins dock, which turns down their ability to stimulate the brain to cause hot flashes.

“These neurons are super interesting because they are also tied to mood, sleep and appetite. And we know this is a big conglomeration of what happens with women in midlife. They’re hot flashing, their mood is terrible, they’re not sleeping and they gain weight,” Faubion said. It’s not yet clear if targeting those neurons might help with problems beyond hot flashes.

Hot flashes are exactly what they sound like — a sudden feeling of being very hot that’s usually centered around the face, chest and head. It can also cause intense sweating and flushing that can last several minutes. When this happens at night, it’s called a night sweat. Women in menopause may get these occasionally or many times a day, which can be extremely disruptive.

The roughly 400 women enrolled in each of two related studies published Thursday in JAMA, had moderate to severe symptoms, which the researchers defined as having more than 50 hot flashes a week, and an average of 14 to 16 per day.

In each trial, researchers gave half the women the experimental drug, while the other half took a placebo, which does nothing. Neither the researchers nor the women knew who was taking the drug or the placebo. The women kept daily diaries to track their symptoms. After 12 weeks, the women given the placebo were switched to the study drug, and they continued to take the medication for another 14 weeks.

After four weeks, women taking elinzanetant where having about eight fewer hot flashes each day — about half the number they reported before the study started, while women taking the placebo were reporting about four fewer hot flashes a day, a drop of about one-third. The difference was statistically significant, meaning it was unlikely to be due to chance.  After 12 weeks, women taking elinzanetant were reporting having about 10 fewer hot flashes each day on average compared with an average change of about seven hot flashes each day in the placebo group. Women taking the drug also reported their hot flashes were less intense and that they were sleeping better.

By the end of the study, which ran for 26 weeks, more than 80% of the women in the study taking elinzanetant had seen at least a 50% reduction in their hot flashes. Results from both studies were very similar, giving researchers confidence in their results.

The most common side effects in women taking the drug were headaches and fatigue.

In a recent news release, Bayer said it had already submitted its study data to the FDA for approval.

Faubion said it looks like a very promising medication. How accessible it will be remains to be seen.

“More options for women are a good thing,” Faubion said.