By Jon Johnson

Reviewed by Christina Chun, MPH

Rick Simpson oil is a cannabis extract that takes its name from the medical marijuana activist who created it. Simpson claims that applying the oil to cancer spots on his skin cleared the spots within days.

Rick Simpson oil (RSO) is unique in that it contains higher levels of tetrahydrocannabinol (THC) than other medical cannabis extracts.

Although there is some evidence to support the use of cannabis for aiding cancer treatment, the medical community needs more direct evidence of its safety and effectiveness in humans before making any firm claims.

Scientists continue to research potential uses for cannabis products in treating cancer.

What is it?

RSO is a high potency cannabis extract with high levels of THC, along with other cannabinoids.

Many researchers and medical companies are now focusing on CBD oil, which contains mostly the non-psychoactive compound cannabidiol (CBD). However, RSO contains much higher levels of THC, which is the compound responsible for the high, euphoric feeling associated with marijuana.

Although there may be a number of companies selling RSO on the market, Rick Simpson’s website recommends that people make it at home.

According to the website, people should use cannabis from Cannabis indica strains to make the oil correctly. Some people suggest that these strains create a more subdued, relaxed state, which the website suggests is key to assist healing.

What else does RSO allegedly treat?

The main claim behind RSO is that it can treat cancer. However, many RSO supporters claim that it has helped in the treatment of other conditions, including:

• high blood pressure
• infections
• chronic inflammation
• arthritis
• asthma
• drug addiction
• depression
• multiple sclerosis

However, there is little direct evidence to support these claims.

Does RSO work?

Although people may use the oil in any way they choose, the main claim is that RSO can treat cancer. At present, however, there is little to no evidence to support claims that it cures cancer directly.

Researchers have been studying cannabis and THC, the main component in RSO, for many years. Some evidence supports the use of the compound in cancer therapy.

For instance, a study in Molecular Cancer Therapeutics found that a combination of CBD and THC enhanced the effects of radiation therapy in rodents. This appears promising, as it suggests that cannabis compounds might make standard cancer treatment better.

A case study in Case Reports in Oncology also explored the use of cannabis oil in a child with a specific cancer. She was terminally ill, having had no success with standard treatment. Her parents chose to stop standard treatment and give her a cannabis extract in the form of RSO.

Although it did appear to reduce her specific type of cancer, the girl died from other complications unrelated to its use.

This makes it hard to draw any firm conclusions about the effect that the oil would have had on the cancer cells in the long-term, or to call the treatment a success.

Some cancers may respond better to cannabinoids than others. For example, a review in the Journal of Pancreatic Cancer suggests that cannabis may be helpful as an addition to treatment for cancers that involve cannabinoids, which are the cells in the body that respond to compounds in cannabis. One such cancer is pancreatic cancer.

Their research indicated that both THC and CBD could be helpful as a supplementary treatment for pancreatic cancer, and they urged the completion of more clinical studies using cannabinoids for pancreatic cancer.

A separate review in Frontiers in Pharmacology studied the overall body of research into cannabinoids and their effects regarding cancer. The researchers noted that the majority of animal studies find that the active compounds in cannabis are capable of effectively decreasing tumor growth.

Also, although they are limited, the few human studies to date do show promise — particularly in the realm of preventing or slowing the growth of tumors.

These initial results look positive, but it is still too early to make any broad statements about cannabis and cancer therapy. More long-term studies using RSO or cannabis in humans would need to help back up any claims with strong evidence.

Side effects

THC is a psychoactive substance, and some people are more sensitive to it than others.

THC causes the “high” that most people associate with cannabis. As a result, it can cause temporary mental impairment, so people should not use machinery or drive while using RSO.

High doses of THC may also cause a number of side effects involving the brain, such as:

• anxiety
• paranoia
• panic attacks
• hallucinations
• irritability, especially when “coming down”
• disorientation

Physical side effects are also common when using THC, such as:

• dry, red eyes
• dizziness
• low blood pressure
• trouble sleeping
• impaired memory

These side effects are generally temporary and tend to subside as the THC starts to leave the body.

Risks and considerations

The most important thing to remember about RSO is that there is little evidence to suggest that it directly cures cancer. A person should not stop their recommended cancer treatment to switch to RSO.

Much of the research around cannabis in humans supports using the plant as a supportive therapy, such as using it to help deal with side effects of chemotherapy. Anyone looking for alternatives to their cancer treatment should consult a doctor to discuss their options.

Some may also worry that THC and cannabis products may pose some long-term risks, especially to younger people who use it.

One study in Current Pharmaceutical Design noted that teenagers who use cannabis more often may have a higher risk of impaired ability to think than those who do not use it often. Their brains are still developing at this stage, and cannabis may interfere with the process. However, researchers called for more evidence that takes other factors into account.

Rick Simpson’s website also calls for people to make the oil themselves, which may pose a risk in areas where cannabis is still illegal.

Also, the website suggests using solvents to clean the cannabis before use. Improperly handled solvents may also pose a risk to health.

Summary

There is no solid evidence to support the claims that RSO can cure cancer directly.

Although early research shows that cannabis has some promise in the treatment of cancer, it is not conclusive.

Scientists will need to conduct more research in humans, and clinical trials will need to find strong evidence linking cannabis and cancer treatment before researchers can begin to make any firm claims.

RSO may help support cancer treatment in some cases. However, the long-term risks and effects of the oil are relatively unknown.

Anyone wanting to use THC or cannabis during cancer treatment should talk to their doctor before doing so.