All About RSO

RSO is an acronym for Rick Simpson Oil and is one of the many forms of cannabis concentrate. Rick Simpson became a sort of a legend in the cannabis community after using the internet to unashamedly profess his true belief in the healing power of cannabis. He also beamed the instructions to make this concentrate (which later came to be called by his name) out to the whole world. There are other names for this concentrate such as ‘full extract cannabis oil’ (FECO) or ‘quick wash isopropyl’ (QWISO). Simply put, this type of cannabis concentrate is produced by washing cannabis plant material with a solvent that is able to dissolve the plant’s oily essence into a concentrated extract. The most commonly used solvent for RSO is isopropyl alcohol, but any solvent could be used. The main characteristic of RSO is that it is a whole plant extract, meaning nothing is added or removed from the plant’s natural chemical composition. After the initial solvent wash, the runoff from the cannabis plant material is collected, and then must be processed to ensure the removal of all residual solvent and the activation of the cannabinoids. When the word activation is used in regards to cannabinoids, it refers to the decarboxylation of the molecules. The decarboxylation ensures that THC-a (and other “-a” cannabinoids) will lose their “-a” tail, and become activated (or psychoactive), and as a side effect will cause the consumer to feel a mental high. RSO may be unadulterated or may be further refined to remove chlorophyll and lipids, also removed from plant material by the solvent, through a process known as winterization.

Do not confuse RSO with ‘real scientific hemp oil’ (RSHO) or any RSO products made with ‘hemp’, especially those which are manufactured using industrially farmed hemp. Although Rick may refer to his creation at times as ‘hemp oil’, do not allow his choice of names to confuse you and misrepresent the category of the source material. If you go to Rick Simpson’s website, you can see that he uses only top quality THC-rich cannabis in his production of what he calls Phoenix Tears (and the rest of the world calls RSO). In the cannabis world, hemp and cannabis may be the same plant, but each name implies different subcategories of cannabis plants. Hemp is used to refer to legally grown cannabis with less than 0.3% THC, typically used as some type of raw material to produce a secondary end product like fabric. In contrast, the word cannabis is used to refer to strains high in THC but can also include high CBD strains, which are typically used in a medical or wellness sense. So in short, cannabis RSO can feature THC or CBD as its majority cannabinoid, as reflected by the profile of its chosen source material. Be sure to be wary of where your RSO plant material is sourced from, and choose only the lab tested products available in legal Illinois dispensaries.


Many factors influence the resulting end product concentrate, most important being the selection of the source material. The techniques used in post-processing will also play a large role in the makeup, texture, and flavor of the final product. RSO typically has a cannabinoid potency above 90%, but may feature THC or CBD in the majority. RSO generally has a dark brown color in larger quantities, but will take on an amber golden hue when spread thin onto a surface. Its taste is commonly qualified as intense, akin to ‘spicy tree sap’, with a strong odor of the cannabis plant.

This type of concentrate is a whole plant extract, thereby maximizing the potential entourage effects of the selected strain by including terpenes, flavonoids, and all other minor chemicals of the plant. Cresco Labs RSO product lines are strain specific, so there is also no mixing of terpenes from different strains. Smoking cannabis as an ingestion method is not the most ideal avenue. This is mainly because smoke inherently contains carcinogenic chemicals (meaning known to cause cancer), which naturally occur in all forms of smoke as byproducts of combustion. Choosing ingestion in place of smoking would allow a patient to avoid the potentially damaging effects or irritation of smoke. It could also be possible to utilize RSO as a topical treatment. In Rick Simpson’s documentary “Run From The Cure“, Rick proudly tells the world that he believes he cured his skin cancer using his RSO to topically treat himself (To be clear, his claims have yet to be confirmed by mainstream scientific research). Patients can easily release their dose from the RSO package, and consume a measured amount of cannabis concentrate per their treatment plan.

RSO is another great consumption method available to Illinois medical cannabis patients. RSO can be ingested for slow onset and long-lasting efficacy or used as a topical treatment. Cresco Labs has just added RSO to the available product lineup! Please click here to locate the dispensary nearest to you, and discuss this new option with your patient care specialist!

What do you think about RSO? Please tell us your thoughts in the comments below or on Facebook!

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