The popular herbal sleep aid valerian could help ease some of the sleep problems that can come with menopause, a small study suggests.

Valerian root has been used since ancient Greek and Roman times for various health problems, including insomnia. Modern science is split on whether the herb works: some studies have indicated that it can ease insomnia, but few rigorous clinical trials have put valerian to the test.

For the new study, researchers in Iran randomly assigned 100 postmenopausal women with insomnia to take either two valerian capsules or inactive placebo capsules every day for a month.

That type of clinical trial, in which neither researchers nor participants know who is taking the real treatment or the placebo, is considered the "gold standard" of medical evidence.

Overall, the study found, 30 percent of the women assigned to valerian reported an improvement in their sleep quality, which includes factors like how long it takes to fall asleep at night and how often a person wakes up overnight.

In contrast, only four percent of women taking the placebo reported better sleep.

Simin Taavoni and colleagues at Tehran University report the findings in the journal Menopause.
Sleep problems tend to become more common as people age, with studies suggesting that about half of older adults have insomnia symptoms, such as trouble falling asleep or staying asleep.

For women, menopausal hot flashes and night sweats can add to sleep problems.

The current findings are "encouraging," according to Dr. Jerome Sarris of the University of Melbourne in Australia, who was not involved in the study but has researched herbal approaches to treating insomnia, anxiety and depression.

And for women with sleep problems who are interested in valerian, "there is no harm in trying it," Sarris told Reuters Health in an email.

Women in this study reported no side effects, according to Taavoni's team. And in general studies suggest that any side effects from the herb are mild, like headache or upset stomach.

Valerian is also fairly cheap, with 100 capsules generally costing less than $10.

On the other hand, there's no research on the safety of long-term use, according to the U.S. National Center for Complementary and Alternative Medicine.

And despite the positive findings in the current study, there are still questions about valerian's effectiveness. In a recent review of clinical trials on alternative remedies for insomnia, Sarris and his colleagues found only weak evidence that valerian, or other herbs, work.

There was better evidence in support of yoga, tai chi and acupressure.

Lifestyle changes like cutting down on caffeine and getting regular exercise (but not too close to bedtime) are often recommended for insomnia. When those don't work, the mainstream medical fixes include prescription medications and cognitive behavioral therapy.

According to Sarris, future studies should look at valerian's effects on other measures of sleep, like the total amount of time that people taking the herb are able to stay asleep and their daytime functioning.

Women in the current study took two valerian capsules a day, each containing 530 milligrams of valerian root extract. Both the valerian and placebo capsules they used were made specifically for the study.

One question that arises when taking valerian is whether you are actually getting the amount listed on the product label.

A recent report by ConsumerLab.com, an independent testing company, found that of nine valerian supplements sold in the U.S., five had lower amounts of the herb than indicated on the packaging. That included one product with no valerian in it at all.

In the U.S., valerian and other medicinal herbs are considered dietary supplements, and not regulated in the same way as drugs.