What is Rick Simpson Oil (RSO)?

Rick Simpson Oil—often called RSO—is a full-spectrum cannabis oil rich in THC and a wide range of other cannabinoids, putting it in the same category as fan-favorites live resin and rosin. 

But the further behind the curtain you go, the more complicated RSO gets—much like its divisive creator. Depending on who you ask, Rick Simpson is anything from a folk hero to the face of cannabis pseudo-science.

Some claims about RSO are bold, even compared to those made about other popular cannabis products. Testimonials exist saying that RSO has cured serious diseases like stage IV cancer. Simpson himself has called THC the “cancer killer” and claimed that RSO cured his basal cell carcinoma.

Obviously, these beliefs have struck a nerve in the medical field. How did we get here, and what benefits could RSO actually have?

What is RSO and how is it made?

Rick Simpson Oil (RSO) is a THC-rich, full-spectrum marijuana extract. 

RSO’s high THC content is one of its defining characteristics—it’s a big part of what makes RSO what it is. While you can find viscous, full-spectrum hemp extracts that come in syringes, these aren’t technically Rick Simpson Oil. The extract’s proposed (emphasis on “proposed”) benefits depend on it being THC-dominant. 

To make RSO, cannabis is submerged in a solvent like grain alcohol, before being crushed and stirred into the liquid. The mixture is then strained and heated until leftover alcohol evaporates. 

Due to how it’s prepared, the THC in RSO is activated during production, not after. You don’t need to dab it like you would with THCA into psychotropic THC. That step has already been taken care of. (Plus, dabbing or smoking RSO isn’t recommended.)

It’s entirely possible to craft extracts from high-CBD flower using this same technique. They might be labeled “RSO,” but without the defining high-THC content, they’re not RSO.

RSO and the entourage effect

Since RSO is a full-spectrum (or “whole plant”) product, using it could provide the entourage effect: the result of weed compounds intermingling to create a stronger overall effect. Cannabinoids, terpenes, and other plant materials seem to perform at their peak when working together.

RSO isn’t your only choice if you’re seeking the entourage effect, but it’s still a good choice if you want to prepare a full-spectrum concentrate in your kitchen, rather than buying it at a dispensary. You don’t need industrial equipment or years of experience to make RSO. 

Benefits of Rick Simpson Oil

Aside from general research on THC and its potential benefits, we only found one study focused on RSO itself. 

Anecdotes from users and claims by the extract’s creator are responsible for RSO’s reputation. While these give us a jumping-off point, none of the anecdotal claims should be treated as fact or medical advice.

On to the elephant in the room: claims about RSO’s cancer-curing abilities appear to be unfounded. It’s unclear whether the extract even has benefits beyond those of any high-THC weed oil. The study we noted above is impressive (leukemia cells took a dramatic hit), but it hasn’t been replicated since.

You’ll find a few incredible stories floating around, like this one about a young girl allegedly treated with RSO after receiving a terminal cancer diagnosis—but jumping to conclusions is risky. We don’t have the full context for any of these anecdotal accounts, and we don’t know how big RSO’s contribution even was. In most or all cases, the patient received surgery or chemotherapy before trying RSO.

Unsurprisingly, the radical claims about RSO have raised alarm bells within the medical community.  

Don’t give up on your care plan and expect to cure cancer with RSO. But if you find that it helps alleviate symptoms, go right ahead and use it. It’s a lower-risk choice than addictive opioid painkillers like morphine. Just talk to your doctor about it first, as with any alternative therapy.

THC and cancer: are they related? 

Let’s zoom out for a second. To give credit where it’s due, there does appear to be some promise for using THC to treat cancer. 

As far back as 1975, oral delta 9 THC was shown to slow tumor growth in mice. In fact, it was studies like this that inspired Simpson to begin experimenting with medicinal cannabis in the first place; he didn’t create his namesake oil on a whim. 

Over the past several decades, new research has backed THC’s potential anti-tumor capabilities. It may enhance the effects of radiation when combined with CBD; particular terpenes might also boost THC’s potential anti-cancer properties. 

These are promising possibilities, but more research is needed to verify the benefits. However, there’s no proof that THC is a true “cancer killer,” or that it alone can send a terminally ill patient into remission. It’s not a miracle drug, but THC could be an asset to novel therapies. 

Side effects of RSO

First, because RSO is so THC-rich, it will get you high—possibly very high if used in large quantities. And you’re likely to experience some of weed’s common (short-term) side effects:

• Dry mouth and eyes
• Increased appetite 
• Slow reaction time
• Blood pressure changes
• Sleepiness
• Impaired memory

Cut your session short if you experience a more serious adverse reaction. Paranoia, hallucinations, and vomiting are risks, and some users are more prone to experiencing them than others. Potent concentrates like RSO are tricky to dose without overdoing it, especially for first-time users. 

You should always start slow when trying new THC products. Don’t bump up your dose until you’ve given the effects time to settle in (often within 30 minutes if you’re taking RSO sublingually or two hours if consumed via the digestive tract). 

How to use RSO

You can dab a wide range of concentrates, but you can’t dab RSO. It’s intended to be taken orally (either directly or in edibles), sublingually (under the tongue), or applied topically. You don’t need to heat it to convert non-intoxicating THCA into THC. 

RSO isn’t as heavily processed as concentrates intended for vaping or dabbing. It’s also thicker and may contain residual plant materials or alcohol, making vaping difficult and unpleasant. 

Rather than a small pot, RSO and RSO-style concentrates typically come in a syringe. Make sure the syringe is uncapped and the oil is at least at room temperature before squeezing it out with the plunger.