Terpenes might be the latest buzzword in the world of cannabis, but there’s nothing new about these tiny — yet important — organic compounds. In fact, they’ve been around for as long as plants have been on earth, though we still have much to learn about them. For the makers of cannabis topicals (like me), terpenes represent one of the most exciting developments in recent memory, and while nobody’s quite sure of what the future may hold for them, it’s certain to be an interesting ride.
In case you’re unfamiliar with terpenes, here’s a quick background. Found in everything from the tiniest blade of grass to the mightiest redwood tree, these naturally-occurring chemicals give plants their aromas and flavors. They also help repel predators and, in some cases, attract pollinators as well. Scientists have identified around 150 different terpenes in cannabis, though most strains tend to have a dominant “terpene profile” of just a few varieties.
The terpene profile of a cannabis strain will affect how the strain smells and tastes to you, but it could also have a wide range of other effects — though scientists aren’t exactly sure how yet. As a 2019 review in the journal Plant Science put it, “Arguably, the only effect of cannabis terpenes on humans that is unquestionable are the fragrance attributes.” However, some scientists believe that terpenes could have untapped therapeutic properties, and as governments begin to loosen their restrictions on cannabis research, it’s finally becoming possible to get a clearer look at what terpenes have to offer.
Dr. Ethan Russo, one of the world’s most prominent cannabis researchers, suggests that a phenomenon known as “the entourage effect” may be behind terpenes’ medical potential. In a 2011 study published in the British Journal of Pharmacology, he theorized that the chemical interactions between terpenes and cannabinoids “could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections.”
Other researchers have begun to test this theory in recent years, and they’ve found some promising results. For example, a 2018 paper in the journal Cannabis and Cannabinoid Research found that terpenes could be useful for relieving acute inflammation (i.e. the kind caused when you bang your knee against the coffee table). That same year, a study in Medical Cannabis and Cannabinoids showed that terpenes could play an integral role in stimulating the placebo effect — which might help explain why medical cannabis users credit the plant with relieving such a wide range of ailments.
When it comes to cannabis topicals, terpenes can be valuable not only for their potential therapeutic benefits on the body (which we’ll discuss in detail later), but also for the connections they evoke in people’s minds. Put simply, most of us are already predisposed to respond positively to certain terpenes based on experiences we’ve had with them in our lives. This is called “classical conditioning,” which you may be familiar with if you’ve ever heard of Pavlov and his famous dog (it’s also commonly known as sense memory). For example, if you find yourself craving the scent of cloves during the fall, it might be because you associate them — and their dominant terpene, known as caryophyllene — with positive memories from childhood. It sounds strange, but your mind already connects specific terpenes with different aspects of life without you even realizing it.
While the average cannabis plant contains dozens (at least) of terpenes, only a fraction of these are present in any significant quantity. A cannabis plant’s terpene composition can vary widely depending on its strain — or even from plant to plant, since the environment where the plant grows plays a key role in its terpene content — but most tend to contain some combination of these:
It’s rare to find a cannabis topical that contains just one of these, but choosing a product with a particularly rich content of a specific terpene could (potentially) lead to better results, as the effects of the terpene can accentuate the effects of the other ingredients.
For example, many people use bath soaks to help them mellow out and relax. In this case, a product that’s high (no pun intended) in linalool would be a good choice, since studies have shown this terpene can have tranquilizing effects.
On the other hand, someone who’s sore and exhausted from hiking up and down mountains all weekend — a type of patient I often encounter in my Colorado practice — might benefit more from a CBD cream that can soothe their aching muscles while also invigorating their mind. Here, a product that’s rich in limonene would be a good fit, since this terpene’s mood-elevating effects make it a good counterpart for creams that relieve pain and inflammation.
If a brighter, healthier complexion is what you’re after, then a lotion or serum containing alpha bisabolol would be a solid option. Its potential skin-healing abilities make it well-suited for tackling acne and other conditions.
Regardless of what product you choose — or what terpene it contains — it’s important to avoid ones made with artificial chemicals. This includes artificial terpenes, which usually come in the form of synthetic fragrance oils. Because terpenes comprise only a small portion of cannabis’ total makeup, many companies are trying to create a more “sustainable” supply by making substitutes in a laboratory. However, since some synthetic fragrances have been known to disrupt human hormones — according to a 2012 study in the journal Environmental Health Perspectives, synthetic terpenes can “contribute to the production of formaldehyde, glycol ethers, ultrafine particles, and secondary organic aerosols” that can interfere with the endocrine system — it’s best to steer clear of them. For the average consumer, there’s no way to know if a given artificial terpene is safe or not.
In fact, there’s a lot we don’t know about terpenes in general — but that could be changing soon. The National Institute of Health (NIH) recently announced that it would be awarding $3 million in research grants to investigate the role of terpenes (and other previously obscure cannabis compounds like CBN and CBG) in pain relief. Hopefully, this is the beginning of a golden age of cannabis research that can help us finally understand the true potential of terpenes.