What is the difference between hemp and marijuana? The short answer: semantics. The long answer: the difference is a largely misunderstood distinction that now has two correct answers, a legal one and a scientific one. And like all things proven by scientists, it is somehow up for public and political debate.

Thanks to nearly 80 years of federal cannabis prohibition, public knowledge on the topic is limited to rumors and misinterpretations perpetuated online””everything from “hemp plants are male and marijuana plants are female” to “one is a drug and the other is not.”

The legal definitions also have muddied the water as legislators have passed laws at both the federal and state levels defining hemp in the pursuit of both fiber and medicine.

So what exactly is the difference between marijuana and hemp? Let’s start with semantics.

Hemp refers to strains of Cannabis sativa that have been bred specifically for fiber used for clothing and construction, oils and topical ointments, nutritional benefits and a wide and growing variety of other purposes that don’t involve intoxication.

Marijuana is a slang term used to describe strains of Cannabis sativa specifically bred for the potent resinous glands (trichomes) that grow on the flowers and some leaves (buds). While there is some dispute [3] over the origins of the term “marijuana,” it was introduced into popular use by Hearst-era newspapers as a way to instill fear of pot-smoking Mexicans.

Wording aside, both hemp and marijuana are, in fact, the same thing. Although both “hemp” and “marijuana” as we know them are from the same genus, Cannabis, they are also part of the same species, Cannabis sativa. The scientific difference between what we refer to as hemp and marijuana comes from the purpose the strain was bred for.

“The [legal] definition of hemp is a plant that has low THC and perhaps has a higher level of CBD,” says publisher and marijuana cultivation guru Ed Rosenthal. Rosenthal is the author of the Marijuana Grower’s Handbook [4], which was first published in 1984.

“They are different varieties of the same species,” Rosenthal continues. “A hemp plant grown for seed isn’t necessarily the best fiber plant.”

A 1976 study [5] by Ernest Small and Arthur Cronquist published by the International Association of Plant Taxonomy [6], “A Practical and Natural Taxonomy for Cannabis” concludes that both hemp varieties and marijuana varieties are of the same genus,Cannabis, and the same species Cannabis sativa. Further, there are countless varieties that fall into further classifications within the species Cannabis sativa.

There are three known subspecies among these varieties of Cannabis sativa: C. sativa, C. indica and C. ruderalis. In this case the distinctions largely lie in the latitude at which the subspecies evolved, which in turn contributes to a plant’s physical characteristics and effects, to some extent.

As the cannabis plant was bred alongside the growth and collective knowledge of humans, it took on a variety of purposes. Strains of cannabis used for their potent medicine and intoxicating qualities have further evolved due to prohibition; over the last 50 years, growers have largely moved their operations indoors, fueling the innovation inherent in having the power to manipulate the atmospheric conditions of a gardening space. Today’s cannabis flowers are far more potent and perhaps a higher quality than much of the buds we have used throughout history as either medicine or entheogen [7].

And here is where legal definitions and science intersect.

The female cannabis plant grows glands on the leaves of its flowers that contain at least 60 identified and active cannabinoids (among other beneficial compounds) that have a plethora of medical uses. Scientific testing and identification of cannabinoids and other compounds found in cannabis has generated two outcomes: a better understanding of the plant by scientists and researchers, and a slough of misinterpreted information used to set legal parameters to safe access to the cannabis plant.

Specifically, this year’s state-level legislative sessions have been abuzz even in the most conservative of states with hemp-related legislation, thanks in part to the passage of the Farm Bill [8], which included an industrial hemp cultivation amendment that has opened the doors (though not quite the floodgates) to the crop rejoining America’s agricultural landscape.

The result is a confusing state-by-state legal redefinition of hemp from marijuana based on higher levels of the non-psychotropic cannabinoid cannabidiol (CBD) and the infamously intoxicating ∆-9 tetrahydrocannabinol (THC).

“The international definition of hemp as opposed to marijuana was developed by a Canadian researcher in 1971,” says Dana Larsen, author of The Illustrated History of Cannabis in Canada, which will be published later this year. “That was the year that Canadian scientist Ernest Small published a little-known but very influential book called The Species Problem in Cannabis [9].”

Larsen said Small acknowledged there was not any natural point at which the cannabinoid content could be used to distinguish strains of hemp and marijuana, but despite this he “drew an arbitrary line on the continuum of cannabis types, and decided that 0.3 percent THC in a sifted batch of cannabis flowers was the difference between hemp and marijuana.”

“Small’s arbitrary 0.3 percent THC limit has become standard around the world as the official limit for legal hemp,” Larsen continues. “Small clearly noted that among the hundreds of strains he experimented with, ”˜plants cultivated for fibre [sic], oil and birdseed frequently had moderate or high amounts of THC’… thus the worldwide 0.3 percent THC standard divider between marijuana and hemp is not based on which strains have the most agricultural benefit, nor is it based on an analysis of the THC level required for psychoactivity. It’s based on an arbitrary decision of a Canadian scientist growing cannabis in Ottawa.”

“Surely no member of the vegetable kingdom has ever been more misunderstood than hemp,” says David P. West in a report [10] for the North American Industrial Hemp Council in 1998. “And nowhere have emotions run hotter than the debate over the distinction between industrial hemp and marijuana.”

West’s report goes on to debunk many of the pervasive myths surrounding the definitions of the two words and the ramifications of their legal interpretations. The study highlights the reality that although the plants are scientifically the same, varieties are bred for all sorts of purposes, therefore the legalization of hemp strains is not necessarily a defacto legalization of marijuana strains, and they have notable differences.

Nonetheless, Ernest Small’s interpretations of cannabinoid content in strains as a distinguishing factor toward the semantic differences of the plant were eventually written into law when the United States legalized (sort of) the domestic sale of foreign cultivated hemp products for cosmetics, clothing and nutrition.

In 2001, the Drug Enforcement Administration attempted to ban all products sourced from hemp, but lost this battle in the courts. Instead, it clarified that any product containing THC is illegal for sale in the United States [11], excluding hemp products with no levels of THC. The ruling is credited for allowing more imported hemp products into the legal U.S. marketplace.  

“Canada, for example, defines hemp as products of strains of cannabis which produce less than 0.3 percent THC, while many European countries set the THC limit at 0.2 percent,” says Jeremy Daw, author of Weed the People: From Founding Fiber to Forbidden Fruit. “That may seem like a minor difference, but compare to the definition of marijuana in the United States, which (contrary to popular belief) does not use a THC limit at all.”

Daw says U.S. law, according to the most authoritative court decision on the question, Hemp Industries Association v. DEA [12], defines marijuana as all parts of any Cannabis sativa L. plant, except for defined exceptions, which could be assumed to be what the United States government defines as “hemp.”

“Such exceptions include fibers from cannabis stalks and products derived from sterilized cannabis seeds, but explicitly do not include resins extracted from any variety of cannabis plant,” Daw continues. “Popular misreadings of this part of the court case has led to even more confusion about the difference between hemp and marijuana.”

As we enter the age of legal cannabis, distinctions, be they semantic, legal or scientific, are going to be paramount in creating responsible laws for the legal industry. To simplify, it is all the cannabis plant. Cannabis has so many uses and potential uses that humans have largely played a role in its evolution and probably will continue to into the future. Whether or not legal distinctions and semantics will follow science, so far, is anyone’s guess.