Hemp Legal Definitions: Delta-9 THC Limits and Total THC

Laws change; this is not legal advice

In law, "hemp" is not a botanical word. It is a legal line drawn by a THC limit. The statements below are about United States federal law as we read it on 2026-10-22, from the sources cited. A rule can be amended, delayed or reinterpreted, so check current sources and, for decisions that matter, a qualified lawyer. For the plant-science side, see hemp vs marijuana.

Same plant, two legal labels

CRS notes that hemp and marijuana are different varieties or cultivars of the same species, Cannabis sativa, and that a botanical classification can differ from the legal one. [1]

The 2018 definition (still the one in force on the date we read it)

The 2018 Farm Bill defined hemp as the Cannabis sativa L. plant and its parts and derivatives, including extracts and cannabinoids, "with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis." [2] Dry weight means the measurement is made on the dried plant material rather than the wet plant.

Effects of that definition, as the FDA describes it:

• Cannabis and derivatives at or below the limit were removed from the Controlled Substances Act. [2]


• The law explicitly kept FDA's authority over products containing cannabis-derived compounds. [2] Being "hemp" does not by itself make a food, supplement or drug product lawful; see consumer CBD product rules.

CRS notes that this test counted only delta-9 THC, so products containing other cannabinoids were arguably outside federal drug control as long as delta-9 THC stayed at or below 0.3%. [1]

The 2025 change: total THC

Congress amended the definition in Public Law 119-37, enacted November 12, 2025. [1] Per CRS (August 17, 2026 note, read 2026-10-22), the new definition is scheduled to take effect on November 12, 2026 and then:

• Measures total THC, including the acid form THCA, at not more than 0.3 percent on a dry weight basis. [3]
• Explicitly includes industrial hemp. [3]
• Excludes hemp-derived cannabinoid products (intermediate or final) containing cannabinoids that are not capable of being naturally produced by the plant, or that could occur naturally but were synthesized or manufactured outside the plant. [3]
• Excludes final hemp-derived cannabinoid products with more than 0.4 milligrams combined total, per container, of total THC and other cannabinoids with similar effects. "Container" means the innermost packaging in direct contact with the retail product. [3]

Products excluded in this way would no longer count as hemp and would instead be regulated under the Controlled Substances Act as marijuana. [3] The Justice Department's April 2026 rule also notes that the hemp definition is being amended effective November 12, 2026. [4]

What is still undecided

• Timing. CRS reports that on August 8, 2026 the Senate passed a continuing resolution that would delay most of the new definition until December 11, 2026, while other proposals would delay or repeal it. [3] We did not verify the outcome. Check congress.gov before relying on any date.
• Lists. The law directs FDA to publish lists of cannabinoids that can occur naturally in the plant; CRS says that, as of August 2026, this had not been published. [3]
• Other countries. We did not read other countries' hemp definitions for this page; see cannabis and CBD laws by country.

Why it matters for products

Labels, testing and the "total THC" idea are explained in total THC and total CBD. Intoxicating products are covered in intoxicating hemp-derived products.