RSO syringes on a table next to a bowl of cannabis flower

Rick Simpson Oil (RSO): What is It, How It's Made, & More

Rick Simpson Oil (RSO) is a unique and potent cannabis concentrate that has gained attention as some enthusiasts report experiencing potential therapeutic benefits. But is there any truth to these claims?

In this guide, you’ll learn more about: 

  • What is RSO?
  • The Story of Rick Simpson
  • Does RSO Work?
  • How Do You Dose RSO?
  • Frequently Asked Questions 

What Is RSO?

Rick Simpson Oil, or RSO, is a concentrated form of cannabis oil, and it’s named after its creator, Rick Simpson. The full-spectrum extract, also called whole-plant extract, is renowned for its potential medicinal properties and high potency because it contains all the marijuana plant’s cannabinoids, including THC and CBD, terpenes, and other compounds.


RSO oil is typically made using a complicated solvent extraction method2 and should not be made at home. In this method, cannabis flower is soaked in a solvent, such as ethanol, to dissolve the cannabinoids. The mixture is then heated to evaporate the solvent, leaving behind a thick, dark oil that’s rich in cannabinoids.

Interested in trying RSO? It’s best to leave the production to the professionals and find RSO at your local dispensary. RSO production is an extremely risky and volatile process that should be left only to skilled professionals. Solvent fumes can easily catch fire from an open flame or a spark, leading to potential explosions. Be safe and responsible by purchasing RSO from your local dispensary. 


Rick Simpson Oil is known for its high THC content, making it one of the most potent cannabis oils available. Since RSO is a full-spectrum oil, all the cannabinoids contribute to the entourage effect.


There are many ways to consume RSO, all of which depend on personal preference:

  • Orally: Place a few drops of RSO, straight from the syringe, under your tongue.
  • Topically: Apply the oil directly to your skin.
  • Capsules: Place drops of RSO in a capsule and swallow.
  • Edibles: Add RSO to beverages or sweet and savory dishes.
  • Smoking: You can top your flower with RSO or add it to a pre-roll.

The Story of Rick Simpson

Rick Simpson, a Canadian engineer and medical marijuana activist, started using hemp after a head injury. In 2003, he was diagnosed with skin cancer and created RSO after reading a 1975 study3 suggesting that cannabis may have inhibited cancer tumor growth in mice. Simpson claims that topical application of the cannabis concentrate cured his cancer. 

He began producing and giving away his oil for free while advocating its potential medicinal benefits, like RSO oil for pain. The Canadian police raided his property in 2009, and Simpson now lives in Croatia.4

Does RSO Work?

The effectiveness of RSO is a topic for ongoing debate and research. While there are numerous anecdotal reports of RSO5 providing relief from ailments like cancer, chronic pain, and multiple sclerosis, scientific evidence remains limited. Studies indicate cannabinoids like THC and CBD may have therapeutic potential, but more rigorous clinical trials are needed to confirm the efficacy of the oil.6

How Do You Dose RSO?

Because of RSO’s high potency, budtenders and enthusiasts advise starting slowly with a low dosage. Beginners can start with a small dose, about half the size of short-grained dry rice, and gradually increase it over time. Monitor the effects and adjust the dose accordingly. 

You can also chat with your budtender or licensed medical marijuana physician for personal advice.

Frequently Asked Questions

Want to know more about what is Rick Simpson Oil? Here are the most frequently asked questions and answers:

What’s the difference between RSO oil and cannabis oil?
RSO is a specific type of cannabis oil that has a high THC level and retains a full spectrum of cannabinoids and terpenes. In contrast, cannabis oil may be more refined and contain isolated cannabinoids, such as CBD oil, which mainly contains CBD and little-to-no THC. 

Does RSO contain THC?
Because of its full-spectrum nature, RSO contains high levels of THC.

Does RSO work?
Medical marijuana patients (like Rick Simpson) and cannabis enthusiasts anecdotally share reports of RSO’s effectiveness, but scientific evidence is limited. More research is needed to conclusively determine the oil’s efficacy.

Purchasing RSO

RSO is a very potent cannabis oil that shouldn’t be made at home. Buy high-quality Rick Simpson Oil from a reputable dispensary before using it for its potential medicinal properties or exploring new ways to use cannabis. Talk to your budtender if you want to know more about RSO.



1. “What Is Rick Simpson Oil,” Leafwell,

2. “What is Rick Simpson Oil (RSO)?” Weedmaps,

3. “Antineoplastic activity of cannabinoids,” National Library of Medicine, September 1975,

4. “What is Rick Simpson Oil? Your complete guide to RSO,” Leafly, June 9, 2022,

5. “Can Rick Simpson Oil help treat cancer?” MedicalNewsToday, May 24, 2023,

6. “Comparison of the efficacy and survival analysis of neoadjuvant chemotherapy for Her-2-positive breast cancer,” National Library of Medicine, September 21, 2018,


This content is not intended as medical advice. The information provided is meant to encourage cannabis education, not replace direct patient-healthcare professional relationships.  Always consult your primary care physician or other healthcare provider prior to using cannabis products for treatment of a medical condition.  Any statements contained herein have not been evaluated by the Food and Drug Administration. Products referenced are not intended to diagnose, treat, cure, or prevent any disease.  Products are only available where consumption of cannabis is legal.