Terpenes are the aromatic compounds found in marijuana, and it seems they are finally stepping out of the shadow of cannabinoids such as CBD and THC. For decades, it was assumed that terpenes did little more than enhance the scent of cannabis, but recent research has revealed that both terpenes and cannabinoids are more effective together in what is known as the ‘entourage effect.’
It is also a fact that terpenes have an impact on the human body when acting alone. The notion that terpenes directly affect brain function is obvious now, but in the past scientists found it hard to differentiate between the direct impact of terpenes on the brain, and their indirect impact on mood. As it happens, our sense of smell is linked to the brain’s memory and emotion centers, which means terpenes have the capacity to hold powerful influence over our greater psyche.
As a result, there is a probable link between the scent of a terpene and its effect. It is likely that terpenes modulate the behavior of the brain’s cells, which of course has a significant effect on brain processing. Marijuana produces an enormous number of terpenes and like its cannabinoids, some are better known than others.
In this article, we talk about one of the most well-known cannabis terpenes of all — Linalool.
Linalool is found in over 200 plant species aside from cannabis, and it has a litany of uses. As a naturally occurring terpene, linalool is known for its lovely floral scent and is one of the main ingredients in essential oils such as lavender. It is typically used in up to 80% of perfumed hygiene products, as well as cleaning agents like soaps, shampoos, essential oils, and detergents.
You will probably be amazed to learn that the average person who doesn’t smoke weed, consumes up to two grams of linalool per year, such is the number of products that the terpene is included in. Here is a short list of some of linalool’s many uses:
Linalool exhibits all of the characteristics and properties associated with an anti-inflammatory agent. According to the Journal of Phytomedicine, linalool and its corresponding compound acetate play a significant role in the anti-inflammatory activity that is displayed by any essential oil that contains the terpene.
Given lavender’s reputation for promoting restful sleep, it is hardly a surprise that linalool is also known for its sedative and calming effects. Evidence of its sedative effects came almost by accident, when a 2008 study tried to find proof that linalool possessed anxiolytic properties. Instead, the research found that it had strong sedative qualities. There is also evidence to suggest that linalool enhances the effect of sedatives including pentobarbital.
A 2003 study found that the terpene was an effective analgesic. As a monoterpene compound, linalool is in a large portion of essential oils extracted from plant species that give off a sweet scent. Medicinally, most of these plants are used for their painkilling properties.
It is also possible that the terpene’s pain-killing capacity is due to the fact that it elevates adenosine levels, which is a brain chemical that is blocked by caffeine. A 2007 study by Kim et al. found that in obese patients who underwent gastric banding surgery (and were exposed to linalool-containing lavender oil), only 46% required opioids after the procedure. This compares favorably to the control group, as 82% of them required pain medication.
Anti-Depressant & Anti-Anxiety
Another study published in 2016 looked at the impact of linalool on mice. The test exposed the mice to vapors from the terpene, and they showed a decreased level of anxiety and depression-like behavior. Mice exposed to linalool also spent more time in ‘fear-inducing’ environments, and worked harder and longer to escape from a doomed situation.
Meanwhile, a study published in 2009 found that linalool improves the immune system’s resilience to stress. Stress is known to change white blood cell distribution, which causes an increase in neutrophils and a decrease in lymphocytes. The study found that linalool prevented this shift in rats, thus ensuring the rodents were not exposed to typical stress-induced physiological changes. Authors of the study believe the terpene activates our parasympathetic response, which occurs when we digest food or when we are resting.
A further study published in 2016 suggests that linalool could be used as a possible treatment for Alzheimer’s, a disease known for causing the build-up of cellular “tangles” and brain plaque that results in the degeneration of the neurons and cerebral tissue. The study in question looked at mice, and found that the terpene reversed a number of the cognitive and behavioral impairments associated with Alzheimer’s. It also reduced the number of cellular tangles and brain plaques that are commonly part of the condition.
According to a toxicity profile conducted in 1995, linalool was an irritant to the skin of several lab animal species. In humans, it also seems to cause minor skin irritation. The report concluded that it was of “low acute toxicity” when given to rats orally, and also on the skin of rabbits.
A more recent report stated that at concentrations of up to 20%, Linalool was consistently found NOT to be a sensitizer in tests on humans. In other words it was neither phototoxic nor photoallergenic, but it could cause allergic contact dermatitis in some individuals. In animal studies, it proved irritating to rabbit skin, but was not a sensitizer in guinea pigs.
Is Linalool Safe?
While there is a risk of skin irritation and allergic reactions, this terpene is not a skin allergen in its pure form. However, once linalool is oxidized, it is capable of causing adverse reactions or sensitivity in high concentrations. In simple terms, oxidized linalool can cause problems but if you use a pure and fresh linalool extract, or an essential oil containing it, you should suffer no ill effects.
That being said, there have been studies which call into question the safety of lavender oil use. One study in particular by Prasher, Locke, and Evans, published in 2004, found that lavender oil is cytotoxic (causes cells death) at a concentration of 0.25%. This is concerning because the standard recommended concentration for essential oils is between 0.5% and 1%. Linalool and linalyl acetate (another major component of lavender oil) were assessed for their cytotoxicity, and it was discovered that linalool’s activity reflected that of the whole oil; a clear sign that the terpene is possibly the oil’s active ingredient.
Linalool Side Effects
Various studies, along with anecdotal evidence, now seem to suggest that Linalool is a likely skin irritant capable of causing contact dermatitis in sensitive individuals. Once it has been oxidized, it can also become an allergen or sensitizer. Interestingly enough, some experts believe you can prevent oxidation simply by sealing the lid on a container of any product containing linalool.
As such, it seems that linalool only causes allergies when oxidized. As for why people become sensitive to the terpene, medical researchers are unable to agree, although it almost certainly involves the immune system. For instance, allergic contact dermatitis occurs when your skin reacts after exposure to a foreign substance. Once you develop an allergy to linalool, it only takes a small amount to trigger a reaction.
If you have a known linalool allergy, be sure to avoid essential oils including Howood, Rosewood, Coriander, Linaloe, Lavender, Bergamot, and Petitgrain. Other potential side effects of linalool exposure can include facial psoriasis and eczema. One study tested 3,000 patients who had eczema by rubbing a patch containing oxidized linalool on their skin, and results showed that up to 7% of them displayed an allergic to the terpenoid.
Final Thoughts on Linalool
There is no doubt that linalool offers a wide array of benefits. It possesses antimicrobial and anti-inflammatory properties, improves sleep, reduces anxiety and stress and helps with skin conditions in individuals who are not allergic to it. You will find it in dozens of essential oils, including lavender, which means it is easy to find.
However, oxidized linalool can cause allergic reactions in a certain percentage of the population, and side effects include skin conditions such as eczema and contact dermatitis. If you use essential oils and are suffering from an allergic skin reaction, perform an allergy test to see if linalool may be the cause.