An Indian herb, ashwagandha, has been long said to improve sleep, but it was never quite understood how, until now. Japanese researchers at the University of Tsukuba identified an active component in the leaves that help induce sleep.

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In their study, published in PLOS, the scientists tested numerous components of the leaves on mice by using a neurological test (EEG) to identify problems related to electrical activity of the brain.

In a water extract from the leaves, large amounts of the triethylene glycol (TEG) were present, which were found to significantly increase non-rapid eye movement sleep and slightly change rapid eye movement sleep, according to a news release.

The authors note the ashwagandha leaves could be potentially used for insomnia therapy. About 1 in 10 adults have chronic insomnia, according to the American Sleep Association. Chronic insomnia involves having symptoms for at least 3 nights per week for a month. Some of the symptoms include disturbances in sleep pattern, daytime tiredness, irritability, and difficulty paying attention.

Unlike current synthetic drugs that are available to treat insomnia, ashwagandha is natural and promotes sleep without negative side effects.

To confirm the safety of TEG and its clinical application, the researchers indicate further research needs to be done.

Ashwagandha, typically sold in pill form, has also been promoted to relieve symptoms of arthritis, stress, and other conditions; however, there is insufficient scientific research to fully support its effectiveness.

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