Rick Simpson Oil (RSO) is an unrefined, potent oil extracted from cannabis using ethanol. It's named after the man who created it and first benefited from it. Canadian Rick Simpson claims he cured his own skin cancer with a custom blend of cannabis oil, which has come to be known as Rick Simpson Oil (RSO), or Phoenix Tears (the name of Rick's website). Since then, he has touted the benefits of medical marijuana and used to give away his eponymous oil for free.

Find cannabis concentrates from licensed vendors near you. 

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Who is Rick Simpson and why did he create RSO?

In 2003, Simpson was diagnosed with basal cell carcinoma, a skin cancer. Soon after his cancer diagnosis, he read a study from the Journal of the National Cancer Institute that showed THC appeared to reduce the growth of tumor cells in mice. Simpson was already a fan of medical cannabis and had been using it to treat tinnitus and dizzy spells caused after falling and hitting his head several years earlier. So he decided to try to treat his skin cancer with cannabis oil.

According to Simpson's account, he whipped up a homemade extract, applied it directly to the cancerous moles, and covered them with a bandage. Four days later, he claimed, he removed the bandages and the growths were gone.

Simpson then began growing and cultivating his own cannabis to perfect a custom oil blend. After health and government groups like the Canadian Cancer Society ignored his discovery, he set out to promote the medicinal effects of cannabis to others. He created a YouTube documentary, Run From the Cure,and wrote a book, The Rick Simpson Story. Until 2009, when he was ordered to stop for legal reasons, he gave away RSO for free.

Controversy and copycats

While he's one of the most well-known personalities within the medical cannabis community, Simpson has also caused controversy and skepticism. He has drawn some ire from physicians and medical professionals for his lack of scientific research or clinical trials to back up his claims.

Simpson still has his share of defenders who have claimed to have successfully used his blend of oil to cure cancer. However, on his website, Simpson states that he no longer produces or supplies his oil due to its illegality in many countries. He also articulated his wish to disassociate himself with any online vendors who claim to supply Rick Simpson Oil.

Simpson claims that the only way to ensure patients have his blend of oil is for patients to produce it themselves. Simpson's site has instructions and an FAQ. In addition to solvent, which is highly flammable, the recipe for RSO includes a number of household items, including small containers, coffee filters, an electric rice cooker, a large fan, a stainless steel measuring cup, and a coffee warmer or oven. The recipe available on his website demonstrates how to produce the full 60 grams of RSO oil for his recommended 90-day treatment period.

In the US, be aware that it's illegal for non-professionals to produce solvent-based concentrates like RSO. In addition, making RSO is dangerous — work areas need to be well-ventilated with no agents (sparks, open flames, etc.) that could ignite the solvent fumes.

If you are interested in trying RSO, it's much safer to buy it from a licensed vendor. 

How to use RSO

Simpson has dosage instructions on his site, but keep in mind they have not been vetted by medical researchers. Dosages vary from person to person depending on many factors, including the potency of the RSO, which Simpson claims is 80% to 90% THC.

RSO is typically not smoked. It is applied in the following ways:

  • As a topical rubbed onto the surface of the skin
  • As a sublingual (under the tongue) for the fastest absorption rate
  • As a capsule taken orally for slowest-acting effects that last longer

The difference between RSO and CBD Oil

CBD oil derived from industrial hemp plants contains only cannabidiol (CBD), while RSO has a high concentration of THC — at least 20% — and the full range of cannabinoids found in the cannabis plant. It's also important to distinguish RSO from other products labeled as hemp oil and hempseed oil, as these products often don't contain any CBD or THC. RSO is highly intoxicating because of the THC content. In other words, it'll get you high while CBD won't.

CBD oil dropper Photo by: Gina Coleman/Weedmaps

Rick Simpson Oil benefits

There remains a need for more research to support the purported effectiveness of RSO and other cannabinoid-based concoctions. But there are already indicators that cannabis could be a powerful tool in combating cancer and the detrimental side effects of its treatment. The antitumor properties of cannabinoids in cell lines and in animal models induced with cancer have been well-documented in peer-reviewed research over the years, but more research is needed to prove the efficacy and safety for clinical trials involving human patients. 

Is RSO considered a full spectrum cannabis oil?

Full-spectrum cannabis oil (FSCO) is cannabis oil that includes the full range of bioactive compounds found in cannabis without altering their composition. This includes flavonoids, phenols, fatty acids, and, most importantly, a variety of terpenes and cannabinoids in their natural acid form.

While the RSO process does extract the full range of compounds, the process of removing the solvent from the solution requires heat. Heat changes the cannabinoids from their acid form into their activated form in a process called decarboxylation (i.e. THCA decarboxylates into THC and CBDA into CBD). The heat also volatilizes most of the terpenes that were initially extracted, leaving an oil that may not have all the bioactive compounds that were available in the plant's trichome glands.

DISCLAIMER: The production of cannabis oils such as Rick Simpson Oil (RSO) is illegal in most jurisdictions. Additionally, producing the oil involves volatile compounds that are dangerous in the hands of inexperienced technicians with improper equipment and ill-equipped facilities. The methods described may prove dangerous or illegal. Any action you take upon the information provided here is strictly at your own risk.

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The information contained in this site is provided for informational purposes only, and should not be construed as medical or legal advice. This page was last updated on October 8, 2021.