“It might be available at the local 7-11 in Pennsylvania,” said Dr. Lee “but any product you get on the market is not federally regulated by the F.D.A, so the purity and safety and quality are questionable.”

Indeed, a recent study that evaluated dozens of CBD products ordered online found that nearly 70 percent were not labeled accurately and had either higher or lower concentrations of the ingredient than indicated on the label. Some also contained THC.

Dr. Hurd, who has been studying CBD for nearly 10 years, warns that the expectations around the substance are unrealistic. “People are making it out to be a nirvana kind of drug, and that’s a problem,” she said. “One compound cannot cure everything.”