Cannabis, one of humanity's oldest cultivated crops, has been used for over 12,000 years for its diverse properties, including food, fiber, medicine, and mind-altering effects. Today, the global cannabis industry is worth an estimated $65 billion, with consumers having access to more than 700 strains, often bearing colorful names such as Cat Piss, Purple Monkey Balls, and Unicorn Poop.

Despite this remarkable diversity, cannabis products are primarily categorized as either indica or sativa, each with purportedly distinct psychoactive effects. As Alex Pasternack, co-founder and president of the international cannabis brand Binske, puts it, "People think that if you smoke an indica, it's like taking a Xanax and you're going to be falling asleep, whereas a sativa is almost like doing a line of cocaine and you're going to be jacked up and hyper." This dichotomous labeling system is deeply entrenched among consumers worldwide, from California dispensaries to Dutch 'coffee shops' and Bangkok smoking lounges.

However, mounting scientific evidence suggests that these labels are largely meaningless, with no significant chemical or genetic differences between the two, implying that consumers may not be getting the specific effects they seek. Pasternack emphasizes that "the idea of indica-sativa is heavily misconstrued."

The origins of the terms 'indica' and 'sativa' can be traced back to the late 18th century when French biologist Jean-Baptiste Lamarck proposed classifying cannabis plants by their physical appearance. Indicas were described as shorter with woody stems and thick, stubby leaves, while sativas were taller with fibrous stems and feathery, thin leaves. However, as neuroscientist Nick Jikomes, previously the director of science and innovation at the cannabis e-marketplace Leafly, points out, "Rather, the way a drug makes you feel is due to its chemistry," and not simply its appearance.

Moreover, cannabis growers are not bound by strict naming conventions, unlike vintners, cheesemakers, or apple growers. Jikomes explains, "I could go grab random cannabis seeds from someone and call it Blue Dream or Girl Scout Cookies. I could even give it my own new name that I make up, and call it an indica, sativa, hybrid, or whatever I want." This lack of standardization contributes to the inconsistency between a product's label and its actual chemical composition.

In a 2022 study, Jikomes and his co-authors from the University of Colorado, Boulder analyzed the chemical makeup of more than 90,000 commercial cannabis flower samples collected from six U.S. states. They discovered that a product's label poorly reflected its chemistry, with sativa strains not necessarily containing higher amounts of tetrahydrocannabinol (THC) compared to indicas, despite the common belief that sativas produce energetic and euphoric effects.

These findings were echoed by another study published a year earlier, led by Sean Myles, an associate professor of agriculture at Nova Scotia's Dalhousie University. After analyzing nearly 300 cannabis strains, Myles concluded, "There's certainly no scientific evidence that there's any consistent difference between samples with those two labels. It's all kind of nebulous."

The extensive cross-breeding that has occurred over time has contributed to the blurring of distinctions between the original indica and sativa plants. Myles explains, "things are now too mixed up" for there to be a clear distinction.

To improve accuracy, researchers suggest classifying cannabis according to its chemical attributes, including cannabinoids and terpenes, rather than its physical appearance. Every cannabis plant contains some 540 chemical substances, including more than 144 different cannabinoids, such as THC and cannabidiol (CBD), which produce specific medicinal and psychoactive effects. This alternative labeling system would list the key compounds present in a particular cultivar, alongside their respective amounts, similar to the 'Nutrition Facts' panel found on food packages.

Terpenes, another type of biologically active molecule produced by the plants, heavily influence a strain's flavor and aroma. Some experts believe they also interact with cannabinoids to tweak its effects, in what's called the 'entourage effect'. Pasternack notes that the musky-smelling myrcene is "thought to have more psychoactive effects for THC," while the citrusy limonene has "more elevated mood and stress release."

Classifying cannabis using terpenes also makes sense from a genetic standpoint. In their respective studies, Myles and Jikomes determined that strains can be sorted into a handful of groups, such as limonene, myrcene, caryophyllene, and pinene, based on their dominant terpene profiles, which can be linked to specific gene expression patterns.

While a chemical profile-based labeling system would be more sophisticated and scientifically accurate, Pasternack acknowledges that today's reality is such that most consumers aren't looking for more information on labels. "People just try to buy whatever the most bang they can get for their buck," he says, adding that "the industry is driven by price point, and the cheapest stuff is usually what moves in the highest volumes."

Jikomes agrees, stating that optimizing price "has been true for the entire lifetime of the industry and doesn't show any evidence of changing." Moreover, the simplicity of the indica/sativa labeling system is another reason for its persistence. "The whole system is just whether you want an upper or a downer," he explains. "It enables retailers and brands to have a universal, foolproof way to market an arbitrary set of products to any consumer, and it's simple enough that anyone can understand it."

In conclusion, while a more sophisticated labeling system based on a strain's chemical profile would be more accurate, Jikomes predicts that the indica/sativa system is here to stay. "Ultimately, you can put as many terpenes on the sticker as you want," he says, "but my prediction is that the indica/sativa system is here to stay."