Cannabis Science

26 June 2019

A closer look at cannabis terpenes

Why terpenes will replace the indica/sativa model

By Georgios Mouratidis

There’s a revolution brewing in the cannabis industry. The good ol’ days of the “sativa versus indica” classification are swiftly drawing to a close. With the increased legalization of cannabis products, cultivators and researchers have had a better opportunity to question the assumptions that have grown around the traditional sativa/indica paradigm.

Yes, these two subspecies of the Cannabaceae family have different botanical features indeed, but the physiological effects often ascribed to them aren’t so clear-cut. Plus, with all the crossbreeding in the cannabis industry nowadays, it’s almost impossible to get your hands on a 100 percent indica or sativa plant (unless you’re DJ Short or Ed Rosenthal). So, without the organizing principle of sativa/indica, how are we to accurately classify cannabis in the 21st century?

One answer is to focus on the cannabis plant’s aromatic compounds known as terpenes. There’s a growing interest in the impressive array of healing effects these compounds offer, especially when combined with certain cannabinoids.

Manipulating terpene levels has always been a big part of the breeding process since it gave many strains their characteristic smell. But, it’s not only about flavor and smell; the terpene profile significantly alters a strain’s physiological effects. In this article, we will explore precisely what terpenes are and how they affect the human body. As you’ll soon discover, measuring terpene profiles represents a promising road forward in the field of cannabis, or more precise, phenotype classification.

Start with the basics: What are terpenes?

Whenever you describe a plant, fruit, or herb’s distinctive aroma, what you’re really talking about, on a molecular level, is its terpene profile. While all terpenes are classified as hydrocarbons, scientists believe they can be arranged in at least 200 ways. How the molecules in each hydrocarbon are arranged determines the effect it has on your olfactory senses.

A diagram of terpenes and their scent profile by Coffeeshop Guru
11 examples of the different scents and medicinal benefits terpenes possess. Brought to you by SCLabs

Botanists believe terpenes are an evolutionary adaptation intended to both ward off pathogens and encourage more friendly, pollinating critters. Luckily for us, the protective properties found in terpenes (e.g., antifungal and antibacterial) often get passed onto humans when we smoke, swallow, or chew them. In the case of cannabis, you’ll find the highest concentration of terpenes in the oily trichomes that appear during the flowering phase.

A close up of trichomes on a cannabis leaf by Coffeeshop Guru
A close up of a cannabis leaf full of juicy, oily trichomes.

These trichomes also contain the therapeutic cannabinoid compounds like THC and CBD. Since terpenes and cannabinoids have evolved in the trichomes over the centuries, some researchers say it’s best to leave cannabis plants alone so these compounds can work synergistically…but more on that later. For those who want more info on terpenes, be sure to check out our previous post in which we go over the basics in greater detail.

Terpenes and Terpenoids: A quick note on semantics

For all the pedantic people out there, let’s make a quick distinction between terpenes and terpenoids. Yeah, you could get away with using these terms interchangeably, but there is a slight distinction that will make you appear super smart, so read carefully: The term “terpenes” is only supposed to be used for the aromatic compounds that naturally occur on the cannabis plant. Terpenoids, on the other hand, are what’s left of the terpenes after the cannabis plant has been dried and cured, which alters the chemical’s atomic structure. For this reason, some people refer to the terpene/terpenoid distinction as “wet vs. dry.” Again, unless you’re a scientist or a stickler for semantics, don’t sweat it if you mistakenly flip-flop these two terms. We do it all the time.

How do terpenes work?

It’s easy to understand how terpenes that already have antibacterial, antifungal, or antiviral properties would confer the same benefits in humans. The trickier question to answer is how terpenes can exert such profound effects on a person’s mental well-being. Although research into terpenes is ongoing, most scientists believe these compounds have such profound physiological effects because they influence the neurochemistry of our brains.

It appears various terpenes activate different neurotransmitters in a strikingly similar way to cannabinoids. Interestingly, many terpenes have been shown to work synergistically with varying cannabinoids in the body’s endocannabinoid system. For instance, certain terpenes can increase or decrease the amount of THC that enters a person’s brain.

Scientists often refer to this natural teamwork between terpenes and cannabinoids as the “entourage effect.” Although research into the “entourage effect” is still in its initial phases, it has led some scientists to promote a hands-off policy when it comes to cultivating cannabis. These researchers believe the cannabis plant already has the perfect ratio of terpenes and cannabinoids for maximal therapeutic benefit. The debate over natural versus artificial cannabis cultivation will most likely become central as the global cannabis industry evolves.

Indica/Sativa: Botany, not biology!

So, why exactly should we replace the indica/sativa distinction with varying terpene levels? The basic answer is that sativas and indicas were divided based on botany, not biology. The traditional classification will have you believe that indicas are best for relaxation and nighttime use, whereas sativas have a more “euphoric” effect and are best for daytime use. However, there’s very little data to support these physiological claims. The truth is that the effects of any cannabis strain has everything to do with the plant’s cannabinoids and terpenes rather than the plant’s indica or sativa dominance.

It is useful to remember that the primary reason botanists divided indicas from sativas had to do with their growth patterns, not their psychoactive effects. Sativas tend to grow better in equatorial climates, are taller, and have thin, light green leaves. Indicas, on the other hand, can grow in colder climates, have wider leaves, and are shorter than sativas. So, the sativa/indica distinction still has its merits for cannabis growers. When we’re talking about the effects cannabis has on a consumer, however, we need to look at cannabinoid and terpene profiles.

Terpenes as a useful tool in classifying biotypes

Fascinating research out of the lab Fundación Canna shows just how critical terpene profiles are for distinguishing between various strains of cannabis. According to recent studies, scientists found they could tell the difference between indica-dominant and sativa-dominant cannabis by merely looking at their respective terpene counts. For instance, indica-dominant strains tended to have extremely high quantities of the terpene myrcene. sativa-heavy strains, however, tended to have substantial amounts of either alpha-terpinolene or alpha-pinene.

From their research, scientists conclude that looking into terpene profiles of various cannabis plants can help cultivators better pinpoint their strain’s unique biotype. The authors of this study went so far as to say terpene analysis should be an essential part of evaluating pharmaceutical-grade cannabis before it goes to market. They warn that different terpene profiles could significantly alter the effects of cannabis strains, which means testing for terpenes, as well as cannabinoids, will be essential for the future of medicinal cannabis.

A few common terpenes and their effects

Now that we know a bit more about how terpenes work let’s take a more detailed look at some of the lesser known and yet still prominent terpenes found in the cannabis plant.

Valencene

Flavor/Aroma: Citrusy, orangey, and resembling grapefruit

Effects: Most of the research looking into valencene has examined the terpene’s potential as a natural insecticide. Amazingly, valencene seems to do just as good a job getting rid of mosquitos, ticks, and other pests as man-made chemical pesticides. Although less is known about valencene’s medicinal effects, some scientists believe it could have anti-inflammatory properties, promotes cognitive function and alertness as well as acting as a bronchodilator.

Cannabis strains with high amounts of valencene: Agent Orange, Jillybean, Tangie, and Clementine

Secondary Terpenes: Nerolidol, Decanal, and Octanal

Geraniol

Flavor/Aroma: Floral, fruity, and resembling the aroma of Geranium flowers

Effects: Like valencene, geraniol is currently being studied for its potential use as a potent insecticide. A few researchers have also suggested geraniol might have antifungal and antibacterial properties worth exploring. For instance, a few analysts claim geraniol could effectively kill bad bacteria like E. coli and fungi like Candida albicans.

Cannabis strains with high amounts of geraniol: Great White Shark, Master Kush, Afghani, and Lavender

Secondary Terpenes: Beta-geraniol and Alpha-terpineol

Terpinolene

Flavor/Aroma: Floral, fresh, citrusy, and woodsy

Effects: Terpinolene usually plays a supporting role in a cannabis strain’s flavor and aroma, but it could take center stage in the future of medicinal cannabis. A few recent studies suggest inhaling terpinolene can help patients with sleep disorders like insomnia. Although more research is needed, some even believe terpinolene could help patients struggling with heart issues and cancer. It also shows promise as an effective antibacterial and antifungal agent.

Cannabis strains with high amounts of terpinolene: Dutch Treat, Sour Tsunami, Sensi Star, Arjan’s Haze #3 and Sour Tangie

Secondary Terpenes: Phellandrene

Ocimene

Flavor/Aroma: Sweet, herbal, floral, earthy and citrusy

Effects: Initial tests suggest ocimene evolved over the centuries to protect plants and herbs from harmful microbes. For this reason, scientists are most interested in ocimene’s potential as an antiviral and antibacterial agent as well as its believed anti-inflammatory and anti-oxidant properties. Besides that, ocimene is the subject in ongoing studies as a potential treatment for type 2 diabetes and hypertension. Also, since ocimene tends to appear in cannabis strains that also have the terpene linalool, some researchers believe these compounds might favorably interact with each other.

Cannabis strains with high amounts of ocimene: Sour Diesel, White Fire OG, Chocolope, OG Kush, Amnesia, and Super Lemon Haze

Secondary Terpenes: β-Ocimene

Guaiol

Flavor/Aroma: Piney, woodsy, Floral and earthy

Effects: Guaiol from the Guaiacum plant has been used for hundreds of years in European folk medicine. Just a few diseases guaiol has been claimed to help with include the common cold, arthritis, gout, and even syphilis. Today, analysts are looking into guaiol’s antimicrobial properties to see if there’s scientific evidence to back up these traditional healing claims.

Cannabis strains with high amounts of guaiol: Liberty Haze, Kali Dog, White Widow, and Chocolope

Secondary Terpenes: δ-3-Carene

Terpenes: The cannabis world’s latest scent-sation

As the 21st century rolls on (please forgive the pun), terpenes are set to take center stage in the cannabis industry. The reason for this shift from indica/sativa to terpenes should be clear by now: terpenes offer a far more reliable way to measure a plant’s physiological effects. Cultivators are already experimenting with harvesting crops for specific terpene profiles. Plus, many cannabis vendors now clearly list terpene counts on their products.

Although there’s debate over how far cultivators should go in artificially manufacturing their terpenes, it’s clear that these aromatic compounds will become more prominent as cannabis legalization increases and we will soon be measuring cannabis effectiveness by the terpene profile rather than the old “indica-sativa” adage.

Post author
Georgios Mouratidis
George is a travel and cannabis writer. When he is not geeking out playing strategy games or reading obscure history facts, he enjoys experimenting with sounds, hiking and taking photos. His life motto is “Enjoy every sandwich”.
See more from Georgios Mouratidis

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