Reviewed by Kevin Harbison, PharmD

If you’re a fan of cannabis concentrates, there’s a good chance you’ve heard of Rick Simpson Oil (RSO). This unique concentrate may not be as popular as other forms of cannabis, but it does have its own niche following of cannabis enthusiasts that swear by it. 

Rick Simpson Oil is an ultra-concentrated cannabis oil originally created by a cannabis activist named Rick Simpson in 2003. Simpson regularly used medical cannabis for a variety of ailments, and he wanted to create a THC oil that could be ingested or applied topically. This developed into what we know today as Rick Simpson Oil - also called RSO - which is a highly potent concentrate with a THC content of around 90%.

“RSO should be reserved for cannabis consumers with high THC tolerances or medical patients with conditions that call for high doses of THC,” said Kevin Harbison, PharmD, a cannabis expert and registered pharmacist at Verilife. While he typically doesn’t see the same interest in RSO as other products like flower, vapes, and edibles, Harbison says there are dispensary patients who regularly ask for it.  

RSO is a dark, sticky liquid that is typically dispensed in a syringe. There are several ways to consume RSO:

• Orally: RSO can be added to food or drinks, or used in cooking the same way as cannabutter. Some consumers choose to encapsulate RSO to avoid the strong cannabis taste.  
  
  
• Sublingually: This method involves placing a tiny amount under the tongue and waiting for it to dissolve. Titrating up the dosage is key as it is very concentrated.  
  
  
• Topically: Consumers who use RSO topically rub the concentrate into the skin, near the area they’re hoping to treat. Because it doesn’t actually enter the bloodstream, the user will likely not experience any psychoactive effects.
  
  

When working with a cannabis consumer in building an RSO regimen, Harbison recommends starting low and going slow. “Cannabis follows a biphasic effect, which means a smaller amount can be more effective than a larger amount. In fact, taking more can amplify the symptoms of medical issues that patients are trying to treat. To find the right dosage, it is recommended that you start with an amount the size of the tip of a pen or an uncooked grain of rice, and gradually increase as tolerable. This will help to mitigate the potential side effects of consuming high doses of THC.”

According to Harbison, the majority of the medical marijuana patients he sees typically consume RSO for symptom management. For example, Harbison works with patients going through chemotherapy who use RSO to help control nausea, vomiting, and cachexia. 

While there is a list of conditions RSO is said to “help,” Harbison says “it’s very important to understand that there is not overwhelming evidence that suggests that patients abandon their current treatments for cannabis. Patients should always discuss RSO with their provider to understand the risks and benefits for their individual condition.”

For recreational cannabis enthusiasts, RSO is consumed for its potency and psychoactive effects. RSO edibles can be very popular with this crowd.

RSO vs. Distillate: What’s the Difference?

RSO and THC distillate may seem similar, but they have very different applications. Distillate is typically a cannabinoid-specific oil (usually THC) that contains little else. This oil does not contain terpenes, although they are often added to mimic certain strains. This is a common method when manufacturers produce vapes. RSO contains a variety of cannabinoids, terpenes, oils, and plant material from the raw cannabis. This creates a thick, syrup-like concentrate that is high in THC. 

What Is the Difference Between RSO and CBD?

The main difference between RSO and CBD is that RSO contains very high levels of THC while CBD contains little-to-no THC. 

How Long Does RSO Take To Work?

The amount of time between taking RSO and feeling its effects depends on how you actually take the cannabis oil. For example, if you ingest RSO with an edible, it can take about 30 minutes to an hour before you’ll feel its effects. If you apply RSO sublingually (in the cheek), it can take just five minutes. Alternatively, if you apply RSO topically, you likely won’t feel any effects because the THC won’t enter your bloodstream. 

RSO is extremely potent, and Harbison recommends discussing use of this product with your primary care practitioner before adding it to your regimen. To avoid unpleasant and unwanted effects, he strongly encourages that you start with the least amount possible and gradually titrate up until desired effects are felt.