Some states are moving to ban a specific compound found in marijuana that's known as Delta-8 THC.
Some companies have started selling products with Delta-8 THC and shipping it to states where marijuana isn't legal.
But it's not completely clear how legal or illegal the compound is. The 2018 Farm Bill allows hemp to be sold as long as Delta- 9 THC is under .3%, but it doesn't address Delta-8 THC.
Experts say the two compounds are very similar.
“The main ingredient is something called Delta-9 THC, which is similar to Delta-8 THC but different enough that the potency of Delta-9 is greater than the potency of Delta-8,” said Daniele Piomelli, professor of neurobiology at the University of California Irvine.
Researchers say Delta-8 THC doesn't produce the same type of high associated with marijuana.
There are still a lot of unknowns about this compound.
Experts say Delta-8 and Delta-9 are similar in terms of their chemical makeup. It's still not known exactly how they differ, and if there are any health benefits to consuming products made with Delta-8 THC.
“The fact is that we have not studied Delta-8 as much as we have studied Delta 9. Delta 9 has been studied in tens of thousands of papers. And only a handful of papers have been published on Delta-8 THC,” said Piomelli.
Experts warn more research needs to be done before companies make medical claims about Delta-8 THC.
More than a dozen states have already blocked the sale of Delta-8 THC because of the lack of research.
Editor's note: A previous version of this story said the Farm Bill allows hemp sold with under .03% of Delta- 9 THC when it should have said .3%. This has since been corrected.