Shakespeare was right when he wrote ‘That which we call a rose. By any other word would smell as sweet’... and it’s all thanks to terpenes. Terpenes are the basic chemical components of the fragrant oils that give plants, herbs, leaves and flowers their unique aromas. Their purpose is to repel or attract certain insects to help the plant to reproduce and withstand environmental challenges.

Terpenes are the building blocks that create each plant’s essential oils, so when you stop and smell the roses, you’re actually stopping to smell a bunch of different terpenes that combine to make the distinctive smell that we associate with roses.

Why Does this Matter for Cannabis?

Terpenes are created in a cannabis flower’s sticky resin glands, where odourless THC, CBD and other cannabinoids are also produced. Just like roses, lemons or pine cones, cannabis plants have their own unique aroma because of terpenes. Cannabis plants typically contain around 200 different terpenes, with 20-30 terpenes being predominant and easier to smell.

Sniff one and you might get a whiff of limonene terpene (the same terpene found, unsurprisingly, in lemons) or gerianol (found in geraniums, bergamot and Earl Grey tea), and each specific scent is thought to help to indicate the effect that the strain will have on your body.

Think of terpenes in terms of aromatherapy or their useage in the wellness industry, citrus scents are often included in cleaning products because they are shown to have an uplifting effect on people’s moods.

A popular theory is the ‘entourage effect’, which is an idea that neurologist Ethan Russo MD examined in a review published in the British Journal of Pharmacology. In Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects, Russo put forward the hypothesis that cannabis terpenes such as limonene, myrcene, a-pinene, linalool, b-caryophyllene, caryophyllene oxide, nerolidol and phytol have therapeutic properties of their own and work as part of an ‘entourage effect’ with THC and CBD to give each strain, or even each plant, its unique properties.

What to Look For

As it stands, much of the evidence of the ‘entourage effect’ is anecdotal and clinical trials are needed to verify it. Unless the plant is lab-tested, it’s impossible to identify all of the terpenes in each one. Look for Licensed Producers that lab test for, and publish, dominant terpenes contained within their products.

But you can follow your nose. Chances are, you’ve probably already noticed strains that take their name from their very distinctive aromas (caused by the terpenes) — from the berry scent of Blueberry and the sweet florals of Lavender, to the smokey fuel flavour of Sour Diesel and the piney lemon zesty smell of Super Lemon Haze.

Terpenes that are known to have specific effects on the body are found in cannabis, so many believe that knowing the terpene make-up of a specific strain can give users an indication of what to expect.

Five Common Cannabis Terpenes

Compared to its cousin THC, which makes up around 20% of a cannabis plant’s biomass, terpenes appear in trace amounts (around 1-2%) and in combination with each other. Together they create the plant’s smell, with the most predominant terpene often being the most obvious aroma.

These terpenes are five of the ones most commonly found in cannabis plants:

Limonene - Most commonly found in lemons and citrus rind, limonene has been said to contain uplifting properties that can help fight anxiety and depression.

Myrcene - Found in most varieties of cannabis (as well as hops, thyme and lemongrass), myrcene has a musky, clove scent and is used in aromatherapy in various concentrations with the intent of creating an energizing effect (at low dosage) and a more sedative effect at a higher concentration.

a-Pinene - Responsible for some cannabis’ familiar ‘skunky’ odour, pinene is also found in pine trees and turpentine, and is considered to have anti-inflammatory properties.

Linalool - Popular in aromatherapy products , linalool has a spicy floral scent and is thought to have a sedative effect that helps relieve anxiety.

b-Caryophyllene - One of the most common terpenes found in cannabis, caryophyllene is the only terpene that has been proven to produce anti-inflammatory and analgesic effects by interacting with the body’s endocannabinoid system (CB2).

Unlike the roses that may smell as sweet by any other name, when it comes to cannabis strains, following your nose could give you an indication of the type of effects and experience you’re going to get, beyond the name of the strain.