As new federal restrictions on hemp-derived THC products are set to take effect this fall, long-simmering confusion around the cannabis plant has returned to the spotlight. The debate is less about botany than about regulation, economics and history.
“It’s one of the world’s oldest domesticated crops,” says Nick Johnson, author of the book Grass Roots. “And it’s also incredibly cryptic. We still don’t fully understand why it produces the compounds it does.”
Cannabis contains more than 480 chemical constituents, according to the Drug Enforcement Administration, but U.S. law focuses almost entirely on one: THC, the psychoactive compound responsible for the plant’s intoxicating effects. Federal policy distinguishes legal hemp from illegal marijuana based on THC concentration, historically allowing hemp to contain up to 0.3% THC by dry weight.
Despite the legal distinction, scientists say the plants are fundamentally the same. “Botanically speaking, both hemp and marijuana belong to a single species: Cannabis sativa,” says Kelly Vining, an associate professor at Oregon State University. The differences, she says, are the result of selective breeding—fiber and seed production on one hand, cannabinoid production on the other.
That nuance has fueled controversy in Congress, where lawmakers are moving to redefine hemp based on THC levels in finished products rather than in the plant itself. The change is intended to close a loophole from the 2018 Farm Bill that allowed intoxicating hemp-derived beverages and edibles to proliferate nationwide.
Industry groups warn the new standard could wipe out large portions of the hemp market, including products containing non-intoxicating cannabinoids like CBD that still carry trace THC.
“Hemp and marijuana were separated politically, not biologically,” says Adam Smith of the Marijuana Policy Project. “It’s all cannabinoids. We just draw lines where it’s convenient.”
Those lines have shifted repeatedly over centuries. Hemp was once a staple crop in colonial America, while psychoactive cannabis arrived later through global trade and migration. Federal prohibition hardened in the 20th century, culminating in marijuana’s placement on Schedule I under President Richard Nixon—a status now being reconsidered following a rescheduling directive from President Donald Trump.
The next chapter begins in November, when the new hemp definition takes effect—reshaping an industry that, once again, finds itself caught between science and statute.
Read the whole article from NPR here.
