Policy Assistant to the Director | Director, Executive Policy Research Program
Nonresident Fellow in Drug Policy
Katharine Neill Harris, Victoria Jupp, and Lisa Pittman, “Mapping Hemp Products’ Legal Status Across US States,” Rice University’s Baker Institute for Public Policy, December 6, 2024, https://doi.org/10.25613/5C1S-Q789.
Hemp is a strain of the cannabis plant that is legally defined as having less than 0.3% delta-9 tetrahydrocannabinol (THC) by dry weight. Delta-9 THC is the primary psychoactive compound in cannabis responsible for marijuana’s so-called high feeling. By requiring hemp to have a low concentration of delta-9 THC, lawmakers meant to ensure that the plant would not cause impairment.
The delta-9 THC threshold for hemp was effective — until it wasn’t. By passing the 2018 Farm Bill, Congress broadly legalized the production and sale of hemp, invigorating a vast market for hemp-derived products. Contrary to the expectations of some lawmakers, many popular hemp products do cause impairment. In jurisdictions with few regulations, it is not uncommon to find hemp products that are more potent than what is allowed in many recreational marijuana markets.
Hemp products with legal amounts of delta-9 THC are available in most states. Manufacturers also use hemp to produce THC isomers — compounds similar to delta-9 THC in structure and effects.
For more information on hemp-derived cannabinoids, see the Drug Policy Program’s brief detailing popular cannabis compounds here.
States are cracking down on the hemp-derived cannabinoid market in a variety of ways. Some have enacted age restrictions without addressing issues such as product potency. Others have restricted product potency by applying the 0.3% delta-9 THC threshold to all THC isomers. However, the weight-based metric still allows heavier items — drinks, edibles, etc. — to contain potent amounts of THC. To account for this, some states have also specified milligram caps for total THC content.
Other states have banned hemp-derived cannabinoids that are created through a chemical process. This effectively removes many impairing hemp products from the market, because naturally occurring compounds such as delta-8 THC exist in minuscule amounts that do not have significant effects unless they are modified with other chemicals.
Several states that allow adult medical and recreational use of marijuana have enacted strict measures to tamp down the hemp market, while others have moved toward regulating hemp and marijuana under a single cannabis umbrella.
The map below shows the legal status of impairing hemp-derived cannabinoids in each state:
| Legend Directory | |
|---|---|
| Legal | Impairing hemp-derived cannabinoids are legally available with few restrictions. |
| Legal, Some Restrictions | Impairing hemp-derived cannabinoids are legally available with some restrictions, such as milligram caps on total THC content, prohibitions on certain product types, and limits on where products can be sold. |
| Heavily Restricted | Cannabinoids that are produced through isomerization are prohibited, or potency caps are so low that legal products are unlikely to cause impairment. Hemp-derived delta-9 THC is still legal. |
| Illegal | Cannabinoids that are produced through isomerization are prohibited, and hemp with any detectable amount of THC is prohibited or only available where marijuana is sold. |
| Mixed | The state has taken the position that impairing hemp-derived cannabinoids are illegal, but enforcement is so limited or locally variable that one classification does not apply to the whole jurisdiction. |
| Term Index | |
|---|---|
| Tetrahydrocannabinolic Acid (THCa) | Refers to THCa, a naturally occurring compound in hemp and marijuana plants that converts into delta-9 THC when it is heated. Some states require the combined amount of THCa and delta-9 THC to be less than 0.3% concentration by weight for legal hemp products in order to limit product potency. |
| Total Tetrahydrocannabinol (THC) | Refers to state potency limits that restrict the total concentration of all cannabinoids, including THCa and THC isomers, such as delta-8, delta-9, delta-10, etc. |
| Isomerization | Refers to the chemical process by which naturally occurring compounds in the hemp plant are modified or transformed into other cannabinoids. State laws may use other terms to refer to this process, including “chemical conversion,” “synthetically derived,” and “chemically modified” hemp derivatives. |
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