What Are Terpenes?
The vast world of aromatic terpenes
The refreshing scents of lemon, pine trees, eucalyptus, and hemp plants all have something in common. Their smell is due to organic compounds called terpenes. Terpenes are a large class of aromatic chemicals found in a wide variety of plants, foods, and essentials oils. In hemp, terpenes are located within the trichomes; tiny, mushroom-shaped crystals that cover the leaves and flowers.
There are more than just a handful of terpenes as well. It's believed that over a hundred exist. Each one has a slightly different chemical structure, and as such provides an exclusive aroma. While they may be appealing to our sense of smell, they are primarily intended to protect plants by repelling bacteria, fungi, and pests.
Fortunately for us, studies have found that terpenes may do more than just provide a pleasant aroma or deter predators. They have also been found to invoke a wide range of biological effects in humans, something we will cover in more detail shortly.
How many terpenes are there, and what are they called?
As we suggested earlier, terpenes are not exclusive to hemp. If you open your kitchen cupboard, you will find everyday food items that also feature high concentrations of terpenes, such as black pepper, mangoes, or lemongrass.
Even though there are over a hundred different terpenes, some are more common than others. Well-known terpenes include the following:
Myrcene is the most prominent terpene found in the Cannabis sativa species, but it also features heavily in clover, sage, hops, and caraway.
Remember the refreshing scent of lemon we mentioned earlier—that's because of limonene. This terpene is used heavily in perfumes, cosmetics, and air fresheners.
Spicy and peppery, beta-caryophyllene is best known for its presence in black pepper, cloves, and cinnamon.
You'll instantly recognise the floral aroma of linalool. It's a pungent terpene most commonly found in lavender.
What makes terpenes special?
Terpenes are significant not only because of their smell, but because of their potential synergy with cannabinoids such as CBD, CBN, and CBG in the human body.
Imagine the hemp plant as a large glass jar. First, we fill that jar with rocks; these are cannabinoids, the largest group of compounds. Next, we use smaller pebbles to fill in some of the gaps; these are our terpenes. Finally, to fill the jar, we pour in sand—flavonoids and other essential molecules. You need all the elements to make a plant whole.
Furthermore, there is evidence to suggest that when cannabinoids and terpenes exist together, their respective biological effects are enhanced. This phenomenon—known as the entourage effect—is what makes the molecules found within hemp unique. However, even in isolation, studies have shown that terpenes may have biological impacts of their own.
What effects do terpenes have?
The scope of potential for terpenes appears vast. A review by the British Pharmacological Society found that terpenes exhibit "unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis‐based medicinal extracts". They went on to add that interactions between cannabinoids and terpenes could lead to "synergy with respect to the treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections".
In short, while cannabinoids may be the stars of the show, they could be even more impactful with the support of terpenes. There is still much more to discover about the inner workings of terpenes, and while we've listed a few common ones above, they are just the tip of the iceberg. In future articles, we will continue to explore terpenes in more detail to find out precisely what they may be capable of.