Unfortunately, treating anxiety, depression, and stress is big business, especially in the United States where anxiety disorders are the #1 most common mental illness, followed at #2 by depression. Globally, 300 million people have depression, and in America, over 10 million adults experience an episode that results in severe impairment each year.
The global anxiety disorder and depression treatment market will be worth over $18 billion per annum by 2023 according to data from Healthcare Market Research and Consulting Services. Even though commonly used medications such as antidepressants and benzodiazepines come with a range of side effects, people still use them in a desperate attempt to change the way they are feeling.
In reality, there is no ‘magic’ drug, and the supposed cure is often almost as bad as the disease. Big Pharma enjoyed a clear run in the market, until now! One of the main reasons why pharmaceutical companies are against the legalization of medical marijuana is because weed could help people in the way that synthetic drugs cannot.
Much is made of the impact of cannabinoids such as THC and CBD on our health, but cannabis also contains terpenes; aromatic compounds used in essential oils, that may be at least partially responsible for some of weed’s therapeutic effects. Myrcene is the most abundant terpene in weed and is getting lots of attention, but there is also a new kid on the block.
What is Limonene?
Limonene is apparently the second most abundant terpene in all of nature and can be found in significant amounts in a wide variety of marijuana strains. As well as its availability in weed, this chemical is also naturally found in the peels of citrus fruits and numerous other plants such as rosemary, pine, juniper, and mint. You’re probably not aware that limonene is used as a flavoring in food, drink, and chewing gum, not to mention medical ointments and cream.
As far as marijuana is concerned, limonene is produced in the trichomes along with other terpenes and cannabinoids. It has its own interaction nodes in the human body, and its medicinal qualities are now firmly under the microscope.
As it is a monoterpene, it is quickly evaporated which means it enables the limonene to rapidly hit the sensory receptors of would-be predators such as parasites or insects. These pests believe the limonene is a toxin and leave the plant alone. With the name ‘limonene,’ it is often assumed that the terpene has a lemon scent. However, there are different scents according to the chemical form. For instance, one chemical form gives limonene a strong tangerine scent, another smells like grapefruit, while others do have the lemon smell.
You are extremely unlikely to experience any adverse effects from high exposure to limonene; one of the reasons why it is used in foods and beverages. A 200-pound person would need to consume around 90 grams of limonene to experience negative side effects, a significantly greater amount than any human is exposed to.
Although it has a low level of toxicity, it can cause skin and respiratory irritation in some people. Symptoms include vasodilation and watery eyes.
Limonene for Anxiety, Depression, and Stress: The Science
According to the ‘entourage effect’ cannabinoids and terpenes work better together. It has been found that limonene has positive interactions with cannabinoids such as CBD-A, THC-A, CBC-A, CBG, and CBC, not to mention fellow terpenes such as linalool and beta-caryophyllene.
Although limonene is not on the list of controlled substances, which means scientists have the freedom to study it, the terpene has only been the subject of more detailed study in recent years. Various studies have found that limonene is a potential anti-inflammatory and modulates the body’s immune system, which may lead to an anti-cancer effect such as shrinking tumors.
As this article focuses on anti-anxiety effects, it is best to go straight into the relevant studies. A study by d’Alessio, Bisson, and Bene, published in the Rejuvenation Research journal in April 2014, found that limonene showed a major anti-stress action in rats under environmental stress.
Another study*, this time by Lima et al., published in the January 2013 edition of Pharmacology, Biochemistry, and Behavior, discovered that when mice inhaled limonene, their anxiety levels were reduced. It was an interesting discovery, especially for those who vaporize their weed. Limonene is highly volatile, so it easily evaporates into a gas.
Being wary of potential interactions is important. A study by Costa et al., published in BioMed Central in February 2013, looked at the impact of bitter orange essential oil on anxiety. The oil contained a significant level of limonene and was effective at reducing anxiety. However, a limonene extract did not have the same effects, possibly because of interaction with other compounds.
All of the above were studies on rodents. Perhaps the most significant study** on humans to date was undertaken by Komori et al. Their work was published way back in 1995 in Neuroimmunomodulation. The team tested the effect of limonene vapor inhalation on 12 patients with depression. Nine of them had a reduced need for antidepressant medication, and also experienced improved immune function and normalized stress hormone.
Although it was a promising breakthrough, the study is almost a quarter of a century old, and there have been few studies on the effect of limonene on humans ever since. While scientists are not completely sure, it seems as if limonene vapor inhalation leads to an increase in dopamine and serotonin in the parts of the brain associated with OCD, depression, and anxiety.
There are still many questions to be answered. For instance, does the terpene directly affect the brain or does it provide stimulation for our brain’s olfactory system?
Which Marijuana Strains Have the Most Limonene?
On average, sativa strains have about 66% more limonene than Indicas or balanced hybrids, yet there are several Indica strains with ample limonene. Overall, it is extremely rare to find more than 1% limonene by dry weight in a marijuana strain. As such, a 200-pound man would need to consume 9,000 grams of a strain with 1% limonene to feel any negative effects, and that individual would probably have far bigger problems to deal with!
The five strains with the highest limonene content are:
- Hindu Kush
- Dirty Girl
- Lemon G
- Blog OG
It is impossible to determine a marijuana strain’s limonene content just by smelling it. Lemon Shining Silver Haze has a strong citrus taste and smell, yet is not in the top 10 strains for limonene content. It is also best to choose a strain with lots of different terpenes. Dirty Girl, for example, contains plenty of alpha-pinene, beta-caryophyllene, Linalool, and myrcene.
Together, these terpenes work with the cannabinoids in marijuana to provide a better therapeutic effect. In general, a sativa-dominant strain with a high limonene content should be your go-to weed if you need a mood boost, but in truth, there are dozens of strains that can do the job.