What Is Valerian?

What it is: The dried root of the plant Valeriana officinalis, also known as heliotrope, was used medicinally in ancient times. Nowadays it is available as tablets, capsules, and tinctures.

Intended uses: As a sleep aid; valerian also used to treat headache or stomach complaints.

What the science says: Valerian may be the most studied herb for insomnia, but results have been inconsistent. Some older studies suggested benefits, but most controlled trials have found that it works no better than a placebo. One problem is that, like all herbs, valerian contains many compounds and it’s not known exactly which one might produce the sedative effect. Thus, there are no standardized doses. Testing by ConsumerLab.com has found that many valerian supplements contain no detectable levels of certain key components or have much less than the labels claim.

Special precautions: Don’t take valerian for longer than two weeks. Long-term use may cause liver damage.

Common side effects: Headache, nausea, diarrhea, morning drowsiness, impaired alertness, “hangover.”

Possible interactions: Alcohol, sedatives.

Our take: We don’t recommend valerian. It may not be more effective than a placebo, and you may not even be getting the “real thing” when you buy the supplements.