I’ve been thinking about terpenes for a while and have finally decided to write about them. I’ve found that the available information about them is, weirdly, both voluminous and difficult to pin down. As a lawyer, my primary focus is on their legality, which has not been addressed at any depth anywhere that I’ve seen. I’ll discuss the legal issues surrounding terpenes in this blog. First, though, I’ll discuss what they are.
A terpene is an aromatic organic hydrocarbon molecule (meaning that it consists solely of hydrogen and carbon atoms) formed by plants and, occasionally, by insects. Terpenes are the primary components of plant resins and essential oils. They are volatile compounds that function to protect plants from environmental stresses, ward off harmful fungus and bacteria, and deter insect predators. They also serve as basic chemical building blocks for more complex molecules, including cannabinoids, some hormones, certain vitamins, and other important organic materials. Their most notable attribute is their aroma. Generally speaking, terpenes emit strong smells. The “skunky” scent of cannabis is primarily due to the presence of terpenes. Any cannabis connoisseur worth her salt will tell you that a wide range of aromas can be detected from cannabis plants, depending on the strain. This is due to the fact that there are more than two hundred types of terpenes found in the cannabis sativa plant. Their respective amounts (the plant’s terpene “profile”) determine the bud’s smell, which can be reminiscent of anything from lemons to diesel fuel to blueberries to pine trees.
Terpenes are associated with the cannabis plant’s health benefits. Certain terpenes appear to provide health benefits of their own and also to assist other cannabinoids deliver their particular benefits. In this way, terpenes participate in the entourage effect, in which the sum of the cannabis plant’s component parts working together is greater than the individual parts working in isolation. This is one of the reasons that so called “full spectrum” hemp oil, which contains more than just CBD isolate, is becoming more prevalent in the marketplace. (It’s also a primary reason that the “big-pharma” isolated molecule/ prescription based medical model is insufficient for cannabis based health care.) Terpenes, in conjunction with cannabinoids, have been shown to be more effective for treating certain ailments than isolated cannabinoids working alone. In a 2011 article published in the British Journal of Pharmacology, “Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects“, Dr. Ethan Russo said of terpenes: “They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts.”
Of the 200+ terpenes found in the cannabis plant, several have gained notoriety, if not household name status. The following terpenes are probably the most prevalent in cannabis. Importantly for our legal discussion, they are each also produced by other plants.
- linalool – occurs in many flowers and spices, including lavender and coriander.
- pinene – occurs more frequently in the plant world than any other terpene.
- myrcene – occurs in mangoes, hops, thyme, lemongrass, and basil.
- limonene – occurs in the rind of the citrus fruit.
- bisabolol – occurs most notably in chamomile.
A discussion of the health benefits of these and other terpenes is well beyond the scope of this blog post. I encourage you to do your own informed research into the medical aspects of terpenes. There is ample reading to be had online, though you should make sure that you’re reading reputable sources. This article, by Project CBD, is a good start. For a deep dive, I suggest this recent article.
Biologically, terpenes form in the cannabis plant’s glandular trichomes, which are specialized to produce and accumulate terpenes. As stated in the “deep dive” article, above, cannabis plants “produce and accumulate a terpene-rich resin in glandular trichomes, which are abundant on the surface of the female inflorescence.” In other words, the trichomes on a cannabis bud produce a resin that is loaded with terpenes.
It is the nature of this biological formation (ie, the “how” and “where” cannabis terpenes are formed) that may have legal consequences for cannabis-based terpenes.
The Controlled Substances Act (CSA) defines “marihuana” (an archaic spelling) as follows: “The term “marihuana” means all parts of the plant Cannabis sativa L., whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin. Such term does not include the mature stalks of such plant, fiber produced from such stalks, oil or cake made from the seeds of such plant, any other compound, manufacture, salt, derivative, mixture, or preparation of such mature stalks (except the resin extracted therefrom), fiber, oil, or cake, or the sterilized seed of such plant which is incapable of germination.” (emphasis added) 21 USC §802(16)
Did you spot the legal issue?
On the one hand, terpenes are unquestionably legal substances. They are not scheduled in the CSA and are abundant in the plant world. The Food and Drug Administration (FDA) has rated them “generally recognized as safe” (GRAS). You consume them every time you add herbs to a salad or pasta dish, bite into a mango, drink chamomile tea and apply essential oils to your wrist, or do any number of other normal things while going about your day. Quite literally, life for most of us would be entirely different without the presence of terpenes.
On the other hand, a plain reading of the CSA’s definition of marijuana (I can’t bear to use the antiquated spelling) clearly brings terpenes derived from the cannabis plant within its purview. If you re-read the definition, above, and pay close attention to the highlighted terms, I think you’ll find that it’s difficult to escape this “plain” reading.
So what does this mean- are terpenes legal? Certainly, terpenes from non-cannabis plants are unquestionably legal. However, the real issue is the legal status of terpenes derived from the cannabis plant. This is virgin legal territory. Although I’d love to say unequivocally that all terpenes are legal, including the ones derived from cannabis, the more logical position is that some terpenes are legal and some are not. Specifically, terpenes derived from marijuana are illegal because they fall within the CSA’s broad definition of “marihuana”. This is strange. Common sense seems to dictate that a particular substance should either be legal or not on its own merits, regardless of its source. However, the reality is that there are all sorts of things that are legal or not based on their source. A watch bearing the name “Rolex” is legal if it came from the Rolex company’s factory, whereas a knockoff is not. A cigar from the Dominican Republic is legal but one from neighboring Cuba is not (or, at least, was not until US sanctions were recently lifted.) Most notably, CBD is legal or not based on its source. This last analogy is the best one. Even the Drug Enforcement Agency (DEA) has acknowledged that CBD is not illegal in and of itself, but rather derives its legal status based on its source. (I’ve written about the DEA’s admission here.) In short, much like CBD, a terpene’s legality is based on its source. If a limonene terpene comes from a citrus rind then it is legal; however, a limonene terpene sourced from a marijuana plant is probably illegal. The molecules may look the same under a microscope but their genealogy, not their chemical makeup, determines their legality.
This is all fairly asinine. The strange legal world we inhabit in which an organic compound is legal or not based on its source is a function of the antiquated definition of marijuana. Setting aside the fact that marijuana shouldn’t be illegal in the first place, the CSA definition was written before the scientific community had a solid understanding of the plant. In its zeal to eliminate “getting high” on “marihuana reefers”, its authors used a blunt legal tool and effectively criminalized a highly complex and poorly understood plant. In so doing it put up numerous obstacles to studying, using, and selling parts of the plant that have nothing to do with getting high. But that’s another discussion altogether and yet another reason to push for full cannabis reform at the Federal level.