Where was lettuce tea invented?

But tiktokers didn't invent lettuce tea. In May 2017, a study was published in the journal Food Science Biotechnology on the possibility of using lettuce as a sleep aid. A scientific experiment was conducted, which confirmed that a natural remedy for normalizing sleep can be obtained from these greens. By the way, in South Korea, lettuce seed oil has long been used as a cure for insomnia in traditional medicine.