Now Reading
What is Rick Simpson Oil?

What is Rick Simpson Oil?

Vial of Rick Simpson Oil

Rick Simpson Oil (RSO) is a heavily concentrated form of cannabis oil which is thought to be helpful in treating cancer.

Rick Simpson Oil has become a DIY medicine that many people credit with reducing or curing chronic illness. Still, many question marks surround the famous but controversial oil.

Here, we explore what is known about Rick Simpson Oil. While much of the evidence for RSO’s efficacy is anecdotal, established research findings point to THC’s anti-cancer and medicinal properties.

Who is Rick Simpson?

Who is Rick Simpson?
Rick Simpson

The man behind Rick Simpson Oil is a Canadian named — not surprisingly — Rick Simpson. Starting in 2003, Simpson began documenting his extraction and use of the oil for his skin cancer via online videos and written posts.

In a series of posts, he shows how he applied the oil in order to treat and eventually, he says, cure his own skin cancer. He also explains how to cultivate cannabis and extract the oil.

When Simpson found out from his dermatologist that several new bumps on his arm were a form of skin cancer called basal cell carcinoma, he turned to cannabis-based medicine. Simpson had used medical marijuana in the past to treat other ailments, including tinnitus and other symptoms from a work-related accident.

As the story goes, he initially watched a documentary about cannabis medicine, and read a study showing that the active compound THC killed cancer cells in mice. So, he created a concentrated cannabis oil and decided to try applying the oil topically.

After he applied the oil for a period of time, the cancer began to disappear.

Simpson believes the oil cured his cancer and is a vocal advocate of cannabis medicine. He embarked on a mission to distribute as much RSO as possible, for free throughout Canada and succeeded in getting it to more than 5,000 people.

How To Use Rick Simpson Oil

Woman pouring RSO to be taken by mouth
(Photo: Shutterstock)

According to Rick Simpson’s website, patients should apply RSO both topically and orally.

On the dosage information page of the website, there is a detailed explanation of how to use Rick Simpson Oil, including dosages and methods. It notes:

“It usually takes the average person about 90 days to ingest the full 60 g or 60 ml oil treatment. I suggest that people start with three doses per day, about the size of a half a grain of short grained dry rice. The patient should take this dosage every 8 hours, early in the morning, then again in the afternoon and then they should take their final dose of the day, about an hour before bedtime.”

After four days at this dosage which should be taken three times a day, most people are then able to increase their doses by doubling the amount of their dosage every four days.

It takes the average person anywhere from 3 to 5 weeks to get to the point where they can ingest 1 gram or 1 ml per day.

The website also makes a point to note that it can take an hour or longer to feel the effects of RSO, and that individual tolerance and interaction with cannabis can vary.

Besides cancer, Rick Simpson Oil has also been reported to work as a treatment for diabetes, epilepsy, asthma, fibromyalgia, pain, migraines and many other conditions.

What Do Experts Say About Rick Simpson Oil?

What Do Experts Say About Rick Simpson Oil?
(Photo: Shutterstock)

Much of the evidence for the effectiveness of Rick Simpson Oil is anecdotal, as RSO has not been evaluated in scientific studies.

Cannabis advocates believe cannabis oil can be helpful for cancer patients, citing existing research into THC’s anti-tumoral effects. But scientists remain skeptical of the ability of cannabis to treat cancer in humans.

Cannabis Advocates Are Supportive

Some cannabis experts believe that anecdotal reports and early trials provide enough evidence to say that cannabis extracts like RSO can treat cancer.

Cannabis extracts have been shown to treat many forms of cancer in many people,” says Mara Gordon, a cannabis extraction expert who works in California’s cannabis industry.

But Gordon also notes that extracts are not a cure-all and do not work for everyone.

“Standard [cancer] therapy should not be foregone,” she says. “However, many patients have achieved remission from terminal cancers reportedly through the use of cannabis extracts. Given the specific details and context of these situations, it is clear cannabis is the direct cause.”

She points to a placebo-controlled trial study that shows cannabis may work together with chemotherapy to fight a form of brain cancer in humans, “which strongly bolsters the already strong anecdotal evidence,” she says.

On some cannabis blogs, Rick Simpson is heralded for “rediscovering” the natural cure for cancer. Some even credit him with unearthing a potential new branch of medicine.

Scientists Remain Skeptical

Though stories about the healing properties of Rick Simpson Oil abound, to date there are no scientific studies on the effects of RSO.

Regardless, some scientific evidence does support the idea that concentrated THC extracts like RSO could have cancer-fighting effects.

A 2000 study showed that cannabinoids inhibited the growth of tumours in mice. And more recently, a 2015 study revealed that other cannabinoids show anti-tumoural effects, as well.

But researchers and scientists are skeptical. They say it’s too early to tell whether cannabis extracts can treat cancer.

Dr. Arno Hazekamp is a researcher with Dutch-based medical cannabis company Bedrocan BV. He has researched homemade preparations of cannabis oil, like RSO.

Dr. Hazekamp notes that while early-stage studies have shown that cannabinoids may be effective in fighting cancer cells, that doesn’t necessarily mean that it works the same way in humans.

“What science says is that some cannabinoids do have an effect on cancer cells, but it’s very unclear if that also happens in real humans,” explains Dr. Hazekamp.

Research on the use of cannabis medicine in humans is limited. A 2006 study conducted in Spain examined nine patients with advanced glioblastoma multiforme — a terminal form of brain cancer.

The patients were split up into two groups. One group was given THC injected directly into the brain, and the other group was given a placebo. Within a year, all the patients had died. But those who received the THC injections lived an average of 4 weeks longer.

“That is the proof we have in people right now. So if anybody says cannabis can cure cancer and it’s scientifically proven, then this is the best proof in real humans that they have,” concludes Dr. Hazekamp.

Controversy Surrounding Rick Simpson Oil

Rick Simpson Oil among other natural and homeopathic remedies, considered fringe.
(Photo: Shutterstock)

Rick Simpson’s outspoken promotion and activism regarding cannabis medicine and his namesake oil has not come without a backlash. His work is considered “fringe”, and is not accepted by the professional medical community.

For example, his medical doctor never acknowledged the health impacts of cannabis oil as a contributor to his recovery, Rick explains in his book, and authorities in Canada regarded him as a lawbreaker.

Simpson also makes a number of questionable claims on his website. For instance, he states that RSO is a “harmless non-addictive natural medication”. But the assertion that extremely concentrated THC oil is completely “harmless” is dubious at best.

Indeed, THC is not without risk. It may be linked to problems with memory and cognition, and studies have shown that strong doses of THC can induce paranoia. And without the tempering effects of CBD, the high levels of THC in RSO can be overwhelming.

Overall, Rick Simpson’s claims about the safety and effectiveness of RSO are biased, and should be treated with some level of skepticism. But to cancer patients, potential risks may be less important than treating their own cancer.

Difference Between Rick Simpson Oil and Other Oils

A woman using marijuana oil
(Photo: Shutterstock)

Rick Simpson Oil

Rick Simpson Oil is not the only extract of its kind, and it’s not everybody’s favorite option.

Cannabis extraction expert Mara Gordon explains that RSO generally refers to a pure extract of THC-rich cannabis oil intended for oral consumption.

“Such oils are usually between 55-85% THC. Most notably, they are distinguished from other concentrated cannabis oils like butane and CO2 oils because those oils are not pre-decarboxylated.”

“The conversion of THCA to THC in butane/CO2 oil happens at the time of combustion or vaporization. Since RSO is meant to be ingested, it needs to be decarboxylated beforehand so the THC is already activated. The original RSO was only THC, but now some people make CBD-rich or CBD-dominant version as well.”


Rick Simpson Oil is by definition high in THC, not CBD. CBD and THC have a seesaw-like relationship in the cannabis plant. When there is high THC, there is low CBD, and vice versa.

CBD and THC are the two most well known compounds found in cannabis. CBD, and in particular a concentrated oil extracted from a strain of cannabis called Charlotte’s Web, has gained household notoriety in recent years.

Full Extract Cannabis Oil

Rick Simpson Oil is also different from other concentrated oils because of the way it is made.

While RSO was the first form of THC-rich cannabis oil to become well known due to Rick Simpson’s personal efforts, there is some controversy over whether the method Simpson used is the best way to extract cannabis oil.

Gordon says a better alternative to Rick Simpson Oil is known as full-extract cannabis oil (FECO), which uses ethanol instead of naphtha as the solvent.

“Using an ethanol process or an olive oil infusion is far better than using petrochemicals or CO2,” she explains. “These processes maximize the extraction of as many important compounds as possible, and the solvent or oil used is food grade.”


Because there is so little scientific study of Rick Simpson Oil, it is impossible for anyone to claim with any certainty that it works for treating or curing cancer.

Some people have reported that they followed Rick Simpson’s method exactly and it failed them, while others have found success.

Although RSO has not been studied scientifically, plausible evidence exists to support its medical benefits. THC, the main component of RSO, shows anti-cancer properties in humans and animals alike.

Due to a lack of human trials, Rick Simpson Oil is not currently accepted by the medical community.

As with all things related to personal health, caution and skepticism are important. Until the legal restrictions and social taboos around cannabis are lifted to make room for further study and deeper understanding, many facts about this potential medicine will remain in the dark.