How Do Terpenes Affect the Endocannabinoid System?

You’re probably familiar with some of the major networks that keep your body ticking, like your circulatory system, endocrine system and nervous system. Lesser known, however, is the endocannabinoid system (ECS)—a network of receptors all animals have. The ECS is designed to respond to endocannabinoids produced by the body; it just so happens that these molecules are quite similar to natural compounds produced by the cannabis plant.

The endocannabinoid system interacts with cannabinoids—it’s right in the name. But cannabinoids such as THC and CBD aren’t the only things that can light up your endocannabinoid system. Other compounds called terpenes affect the ECS receptors too—and even change the way those receptors respond to cannabinoids themselves.

What Are Terpenes?

Wondering what terpenes are, and how they’re different from cannabinoids? Terpenes are found in a wide variety of plants in nature—not just cannabis. Many of the distinctive scents and flavors of plants are largely influenced by terpenes. You might associate terpenes most with herbs like lavender, rosemary and sage, as well as citrus fruits. Strong-flavored terpenes in eucalyptus and tomato plants provide a natural defense from having their leaves and stems eaten by animals.  

But terpenes also play a role in other properties associated with those plants, like the way lavender makes us feel relaxed or a fresh-squeezed grapefruit can be invigorating.

There are other, even more pronounced effects terpenes can produce in the human body. Terpenes like limonene have shown efficacy in preclinical and clinical studies for reducing inflammation. Others, like pinene, can improve bronchodilation, relaxing the muscles of the respiratory system. Studies have also shown that myrcene, limonene and other terpenes demonstrate protective effects for some of the body’s organs, from the cardiovascular system to the digestive tract.

How Do Terpenes Interact With the Endocannabinoid System?

Terpenes interact with the endocannabinoid system in two primary ways—individually or in combination with cannabinoids like THC, CBG, CBN and CBD. This combined action is known as the “entourage effect,” referring to the way the different cannabinoids and terpenes act as agonists or antagonists to activate or deactivate ECS receptors. 

While terpenes might be best known for the cannabinoid company they keep, that doesn’t mean their standalone effects should be overlooked. As the authors of a 2023 study on cannabis terpenes note: “all terpenes, when tested individually, activate CB1 receptors, at about 10–50% of the activation by THC alone.” 

It has been found when terpenes and cannabinoids are mixed, however, the various effects can be more pronounced. Preliminary studies suggest terpenes balance out or reduce some of the side effects associated with certain cannabinoids, like the intoxicating high produced by THC. While researchers continue to learn about the entourage effect—also known as phytocannabinoid-terpenoid synergy—existing studies suggest therapeutic promise.

Should I Look for a CBD Product With Terpenes?

What does that mean for people shopping for products like CBD salves and other cannabis topicals? It means that full-spectrum CBD extract—which contains cannabidiol that’s naturally present in hemp, sub-perceptual and legal levels of THC, along with terpenes and beneficial minor cannabinoids—could give you more relief than products made with CBD that has been separated from other compounds, aka CBD isolate.

Full-spectrum CBD, whether consumed via inhalation, being eaten or applied topically to the skin, benefits from even trace amounts of THC because of the entourage effect phenomenon. The synergy between cannabinoids and terpenes works physiologically on several different levels.

One aspect of the entourage effect is that terpenes and cannabinoids stimulate the same receptors in the body’s endocannabinoid system. For example, researchers found in a 2021 controlled animal study that terpenes including α-humulene, geraniol, linalool, and β-pinene produced the same behaviors as cannabinoids alone in mice by interacting with the same receptors. Another element to the entourage effect is that terpenes produce changes in the body that complement or enhance those produced by cannabinoids, creating a unified, enhanced experience for the consumer. One study found that limonene increased levels of serotonin and dopamine, increasing the feelings of relaxation and stress reduction also created by CBD alone. 

Last but not least, the endocannabinoid system responds more readily to CBD when it’s joined at the receptor by other cannabinoids and terpenes. The latter is not uncommon—many substances are made more bioavailable with the help of another. Vitamin C and iron are one such pairing. Turmeric offers another interesting example. The curcumin in turmeric is associated with several positive physiological effects, including anti-inflammatory, hypoglycemic, antioxidant, wound healing, and antimicrobial properties. 

However, curcumin isn’t well absorbed by the body without the help of other compounds—namely piperine. As one study on curcumin’s bioavailability notes, “In humans, curcumin bioavailability was increased by 2,000% at 45 minutes after co-administering curcumin orally with piperine.”

Or consider vitamin D, which helps calcium go where it needs to in the body and improves the bioavailability of this important mineral. As noted in Current Rheumatology Reports, the mechanism for this is “several vitamin D–dependent calcium transport proteins [which] regulate intestinal calcium absorption.” This dynamic duo supports not only skeletal health, but also cardiovascular and immune functions.

The entourage effects between vitamin C and iron, turmeric and piperine, as well as vitamin D and calcium, don’t depend on an even ratio, either. Even trace amounts of a supportive compound can make a significant difference in bioavailability. The same is true with cannabinoids, which work more effectively when paired with a comprehensive blend of terpenes. 

Is THC in Hemp Legal?

According to the 2018 Farm Bill, the legal difference between hemp and cannabis (marijuana) is that hemp can contain only up to 0.3% of delta-9 tetrahydrocannabinol (THC) by dry weight. Even that sub-perceptual amount of THC, however, can make a big difference in how CBD and various terpenes act in the body. 

Preliminary studies show that terpenes can activate CB1 receptors at about 10-50% of the activation by THC alone. That means that a full spectrum CBD salve like Entourus that’s legal in all 50 states can feel much closer in effect to a product with a 1:1 ratio of CBD:THC that’s only available in a state-licensed dispensary. 

However, unlike those cannabis products available only in legalized cannabis markets, a full-spectrum CBD product that adheres to federal hemp standards won’t produce the adverse side effects associated with higher THC. That’s especially true for cannabis topicals whose effects are localized to the areas where they are applied and are much less likely to produce a high sensation than cannabis products that are smoked or ingested.

In short, the best CBD cream for you—for anyone who wants to maximize efficacy while staying emotionally and cognitively present, for anyone who is concerned about drug testing, for anyone who simply prefers localized effects—is the one with a full complement of terpenes.