You’ve probably heard it said that terpenes are responsible for giving each cannabis strain its unique aroma and flavour, yet in reality they perform a much wider array of functions and can significantly influence the pharmacological effects of your weed. In spite of this, most people only ever bother to look into the cannabinoid profile of their bud, without giving much attention to the different terpenes that are also present.
If you really want to understand a cultivar, though, it’s advisable to learn a thing or two about how much of each terpene it contains.
What Are Terpenes?
In short, terpenes are aromatic compounds that are found in many different types of plant and fruit, and it’s generally these that you’re detecting when you smell marijuana. They are the main ingredients in essential oils, which can be produced from many types of plant, including cannabis.
To be a little more scientific, terpenes are unsaturated hydrocarbons with 10 carbon atoms and 16 hydrogen atoms (molecular formula = C(10)H(16)). By extension, sesquiterpenes (sesqui= one-and-a-half) have a formula of C(15)H(24), and diterpenes C(20)H(32). The term terpenoid refers to any compound with a formula close to a terpene, but which has a slightly different number of carbon atoms and/or additional oxygen atoms. For example, the lavender scented linalool is a terpenoid, because of its molecular structure C(10)H(18)O.
Cannabis plants contain a huge number of terpenes and terpenoids, although the most prevalent are β-caryophyllene and myrcene. The former is known for its spicy, peppery flavour while the latter is generally muskier, although these two compounds provide much more than just taste.
β-caryophyllene, for instance, is the only terpene that acts on the body’s cannabinoid receptors[i], and is considered to be a potent anti-viral[ii]. Myrcene, meanwhile, is thought to contribute to the ‘couch lock’ effect of certain chemovars, so if you’re looking for weed with sedative effects then anything that contains high amounts of myrcene should do the trick.
Other important terpenes include limonene – which is found in citrus fruits and has antioxidant and anticancer properties[iii] – and a-pinene, which has a pine-like aroma and is thought to enhance memory and alertness.
Which Terpenes Are In Which Strains?
Every cannabis plant will contain a combination of many different terpenes, although the concentrations of each of these tend to vary. Differences in terpene profile are caused by an array of factors, including the climate in which a plant is grown, the soil type, the plant’s age and of course genetics.
A recent study in the journal Medical Cannabis and Cannabinoids looked into the terpene content of cannabis inflorescences from 54 popular chemovars, using a technique called gas chromatography to determine the prevalence of each compound[iv].
Results showed that β-caryophyllene was the most prominent terpene in 13 different strains, while β-myrcene was the most prevalent in another 13 strains. However, many cultivars were characterised by high concentrations of other terpenes.
Lemon OG Kush, for example, was found to contain more selina-3,7(11)-diene than any other terpene. Despite its intimidating name, most people are probably quite familiar with this terpene as it is found in hops and provides beer with much of its flavour.
Terpinolene, meanwhile, was found to be the main terpene in Jack Herer, giving this strain a floral aroma while delivering relaxing and anxiolytic effects. Limonene was identified as the principal terpene in Sweet Tooth, while α-bisabolol was the most prominent in Bubble Gum and Berry Deluxe contained more of the terpenoid bulnesol than any other.
Interestingly, the results of this study showed how the terpene profile of cannabis changes as it dries. For instance, fresh Pandora’s Box inflorescences were found to contain more terpinolene than any other terpene, but dried flowers of the same strain contain β-caryophyllene as their main terpene.
What About Essential Oils?
The terpene profile of a cannabis essential oil can often differ from that of the inflorescences from which it was produced. This is because many terpenes are lost or chemically altered during the distillation process.
To prove the point, the same study mentioned above also examined essential oils from 46 different cannabis cultivars, and revealed that the terpenes present in these rarely matched those found in flowers of the same strain. In plant material, it is rare for one compound to account for more than 20 percent of the total terpene content, yet many essential oils contain extremely high concentrations of certain terpenes.
A Key Lime Pie essential oil, for example, was found to contain 65.86 percent β-caryophyllene, while the same terpene accounted for 65.77 percent of the terpene profile of a Gorilla Glue oil.
Using cannabis essential oils therefore doesn’t always provide the same effects as smoking bud, which is just one of the reasons why it really pays to know a thing or two about terpenes.
[i] Gertsch J, Leonti M, Raduner S, Racz I, Chen JZ, Xie XQ, Altmann KH, Karsak M, Zimmer A. Beta-caryophyllene is a dietary cannabinoid. Proceedings of the National Academy of Sciences. 2008 Jul 1;105(26):9099-104. – https://www.pnas.org/content/105/26/9099
[ii] Sharma C, M Al Kaabi J, M Nurulain S, N Goyal S, Amjad Kamal M, Ojha S. Polypharmacological properties and therapeutic potential of β-caryophyllene: a dietary phytocannabinoid of pharmaceutical promise. Current pharmaceutical design. 2016 Jun 1;22(21):3237-64. – https://www.ingentaconnect.com/content/ben/cpd/2016/00000022/00000021/art00015