Before a long run, Flavie Dokken likes to ingest a capsule or gummy with tetrahydrocannabinol (THC), the molecule from the cannabis plant most famous for its psychoactive effects. “It works really well for me. I get an energy boost,” says the U.S. Army veteran and former bodybuilder who’s now a competitive ultramarathoner based in Boulder. During a five-hour run, she might take half a gummy before the workout and then consume the other half a few hours in to give herself a second wind. What she gets from THC isn’t just overall energy but also a feeling of “being tuned in and present during the workout,” she says.