Limonene May Be a Key Component of Cannabis’s Effect on Cancer

Although medical and scientific research on the various components of the cannabis plant has been stunted by what even the DEA admits are outdated federal prohibitions, we have made some tremendous steps into understanding more about the plant and its potential medical properties thanks to independent studies.

Over 100 unique terpenes have thus far been discovered among what Leafly now reports as over 2000 known strains of cannabis (although these numbers may be inflated, and 800 is a more conservative estimate to account for regional creations being named differently).

Limonene in one of the most commonly found cannabis terpenes that’s also commonly found in citrus plants and used in natural insect repellants and cleaners to provide a fresh, bright, citrusy aroma.

It’s also a terpene that’s hailed by medical marijuana patients as helping relieve debilitating symptoms caused by often terminal diseases. We decided to break down the important facts you need to know about limonene and its current and possibly future uses.

Terpenes and Cannabinoids

Cannabinoids (THC, CBD, etc.) account for at least 85 of over 500 natural compounds thus far discovered. These compounds are responsible for much of the physical effects on the endocannabinoid system.

Terpenes make up the aroma (and much of the taste) profile of each strain. Research into cannabinoids (especially THC, as CBD is more widely accepted) is limited, but because the other terpenes aren’t unique to the cannabis plant, research has been performed on terpenes.

In fact, the U.S. National Library of Medicine and National Institutes of Health recognize it as one of the most common terpenes found in nature with a fairly low toxicity.

Studies on mice and rats of both genders showed frequent dosing posed no mutagenic, carcinogenic, or nephrotoxic risk to humans. It also assists with digestion, making it great for gluten-intolerant people.

The NIH and NLM also recognize its potential as an antitumor and chemopreventative compound, though further research has not yet been conducted.

Limonene Sources and Extraction

Limonene can be extracted from oranges, lemons, grapefruits, and limes using a steam distillation method at home, but sterile laboratory conditions are best, as they produce the most pure results with least chance of contamination due to the special training and equipment involved.

It’s also often included in small doses of the terpene profile of shatter, wax, and other cannabis concentrates that are extracted using a much wider variety of methods. The percentage of limonene remaining depends on the extraction method used.

Cannabis extracts most often utilize solvents such as CO2, butane, and and even water, although some now use a combination of heat and pressure (known as rosin). Solvent extracts have the strongest terpene profile (darkest color), while it’s much lower in rosin, which is clear and contains mostly cannabinoids. Limonene can be added later to rosin extract.

Known Medicinal Usage

Limonene is used as a dietary supplement and is a major component of essential oils extracted from citrus peels. It’s recognized as safe in food amounts and safe for most people in medicinal amounts taken orally up to a year.

It has been promoted as possibly having anti-cancer effects, the results are still inconclusive. Survival rates of patients who have been treated with limonene vs traditional chemotherapy treatments is not yet new enough, but it does show up in tumors when taken.

Cancer prevention, weight loss, bronchitis, and other miracle cures are often promised, but clinical studies, while performed, haven’t had enough time to determine yet, and there are too many unknown factors. We know for sure it’s doing something, but can’t be positive what yet.

While limonene appears to have no adverse side effects, skin allergies are possible for those who use beauty or hygiene products containing it. Otherwise it’s widely believed to help relieve anxiety and stress while also improving digestive health.


While limonene’s anti-cancer properties have been grossly oversold by the cannabis industry, it definitely shows promise in the research that’s been done so far. Real medicinal benefits of marijuana can not yet be proven, but enough people are willing to try that we’ll know within a generation or two.

Until then, limonene is an abundant natural resource that reminds us cannabis has a lot in common with many of the fruits, vegetables, herbs, and decorative plants we have around us every day at work, during our commute, and at home.

The DEA may not recognize the medical benefits of cannabis, but other organizations are quickly uncovering the possibilities.

What terpenes have you heard about that you’d like to know more about?



Dr. Brian Penny is a former Business Analyst and Operations Manager at Bank of America turned whistleblower, troll, and freelance writer. You can find his work in Cracked, High Times, HuffPost, Lifewire, Forbes, Fast Company, and dozens of other places, although much of it is no longer under his name. Dr. Penny loves annoying fake media.

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