Rick Simpson Oil (RSO): What It Is, Claims and Risks

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Rick Simpson Oil, or RSO, is a thick, dark cannabis oil, usually high in THC, named after the man who popularized it. We found no clinical trial of RSO itself, and the FDA has not approved a marketing application for cannabis for the treatment of any disease or condition. Its reputation rests on personal stories.

Below is who Rick Simpson is, how RSO differs from other cannabis oils, what people claim it does, and the risks, with each health claim checked against a public health source.

What Is Rick Simpson Oil?

RSO is an unrefined extract, made by soaking the plant in a solvent and boiling the solvent off. People usually take it under the tongue, mix it into food or swallow it in capsules.

It is a highly concentrated cannabis oil, and NIDA notes that cannabis concentrates in dispensaries can have THC concentrations of more than 40%. Because it is so concentrated, a small amount carries a lot of THC.

Who Is Rick Simpson?

The oil takes its name from Rick Simpson. But who is he?

Rick Simpson is not a scientist or a doctor; he has described himself as a Canadian engineer who made the oil after his own health problems. His personal stories, not clinical studies, are what made the oil famous.

RSO Oil vs Cannabis Oil: What’s the Difference?

Florida treatment centers list many oil products, so the difference matters. RSO oil isn’t just your everyday cannabis oil. While both come from the cannabis plant, their extraction methods set them apart. There are various types of cannabis extraction methods out there.

Rick Simpson’s approach soaks the plant in a solvent and boils the solvent off, which leaves a thick, almost tar-like oil darker than most other cannabis oils. The dark color reflects how little it is refined; its strength depends on the plant used and shows only in a lab test.

Claimed Benefits of RSO

Here is what people claim and what is known.

Some users claim it eases their chronic pain, and others use it for sleep or anxiety. Patients in chemotherapy report less nausea; FDA has approved some cannabinoid drugs for that, but RSO itself has not been tested in clinical trials.

Here are the uses people most often report:

Pain relief: personal stories, not trials, are the basis for this claim.
Mood: some say it lifts their mood, while CDC notes cannabis use has been linked to depression and schizophrenia.
Appetite stimulation: increased appetite is a commonly reported cannabis effect, NIDA notes.
Sleep aid: some users take it at night, though NIH says it is unclear whether cannabis improves sleep directly.

Remember, though, that individual experiences can vary. One person’s good report says nothing reliable about how it will affect you. Ask your certifying physician before trying it.

How Do You Use Rick Simpson Oil?

RSO Syringe

An RSO syringe might sound intimidating, but it is simply a way to measure small amounts of a very thick oil. In Florida, the amount should be the dose your certifying physician set in the state registry; RSO is usually placed under the tongue or mixed into food.

RSO Edibles

RSO is sometimes mixed into food. Edibles take longer to show effects, NIDA notes, so do not take a second dose because the first seems slow, and store edibles away from children, who have been hospitalized after eating them.

RSO Capsules

If you’re not keen on the taste or the process of measuring out oil, RSO capsules hold a set amount in each one. They are swallowed, so like edibles they take longer to act.

Is RSO Dangerous?

It can be: RSO carries the risks of any high-THC product, and homemade versions add solvent dangers. The primary concern with Rick Simpson oil is its high THC content, which can be psychoactive. NIDA describes several of those risks.

For instance, NIDA notes that cannabis use has been linked to earlier psychosis in people with a genetic risk and to worse symptoms in people who already have psychotic disorders.

Moreover, consuming large quantities of THC may impair short-term memory, coordination, and judgment. That means not driving, operating machinery or doing tasks that require you to be alert or respond quickly while THC may be affecting you.

User reports of beneficial effects do not cancel out these risks. Always consult a healthcare provider before trying any new product, especially if combined with other medications or if there’s a history of health concerns.

Side effects of RSO

Dizziness: Some users report feeling dizzy after using RSO; if you do, sit or lie down until it passes.
Dry mouth: Like other cannabis products, RSO oil can leave you feeling parched. Drinking water can help.
Increased appetite: Many cannabis products boost hunger. You might find yourself munching more than usual after using RSO.
Sleepiness: Some users report feeling tired or sleepy. Do not drive or operate heavy machinery while RSO may be affecting you; Florida’s physician consent form must include a warning against both.

Where Can I Get Rick Simpson Oil?

Curious about where to buy this? In Florida, marijuana oils such as RSO can be bought only by qualified patients and their caregivers from licensed treatment centers, and each must list its products online, so you can check whether one carries RSO.

If you’re searching for Rick Simpson Oil because you think it might help a health condition, start with a qualified physician. In Florida the first certification requires an in-person exam, and medical marijuana telemedicine services can be used later for renewals with that same physician.

Outside Florida, telehealth rules for cannabis certification vary by state, so check what your state allows before booking a video visit.

Check the medical marijuana law where you live before you buy Rick Simpson Oil. In Florida, a qualified patient needs a physician’s certification in the state registry and an approved medical marijuana card before a treatment center can fill an order. Since April 28, 2026, federal law lists marijuana covered by a state medical marijuana license in Schedule III, while all other marijuana remains in Schedule I, and it is a controlled substance either way.

How Long Does RSO Take to Work?

The way you take RSO changes how fast it works. Taken by mouth, it acts more slowly than inhaled cannabis, NIDA notes, and timing varies with the person and the amount. In Florida, follow the dose your certifying physician set in the state registry, and do not take more because it seems slow.

How to Make Rick Simpson Oil

Thinking about making your own Rick Simpson Oil? We do not give instructions, because solvent extraction has caused serious burns and Florida law makes no provision for doing it at home. Here is why:

Florida patients may not grow cannabis at home, and section 381.986 lets patients buy marijuana and requires them to keep it in its original packaging, while only licensed treatment centers may process it, so state law makes no provision for home extraction.
Home extraction uses volatile solvents: one Colorado burn center treated 29 people burned while making butane hash oil from 2008 to 2014, and 19 of them needed skin grafts.
Solvent left in a homemade oil is never tested, while every batch a Florida treatment center sells has been through certified lab testing.
A homemade oil also has unknown THC content, which turns every dose into guesswork.
Boiling off a flammable solvent indoors near a heat source is the step that creates fire and explosion risk.
Florida patients should ask their physician whether a concentrated oil fits their certification and buy it from a licensed treatment center.

If RSO interests you, the lawful route in Florida is a lab-tested product from a licensed treatment center, and making it yourself is not worth the risk: burn units have treated people injured making butane hash oil, another solvent extract.

Last updated October 15, 2026 by the Dr. Green Relief Editorial Team.

Medical review

Medically reviewed by Achilles Kalnoky, M.D.

Reviewed on October 15, 2026.

He is licensed in Florida as a medical doctor, license ME115088, which you can check on the Florida Department of Health license lookup.

His review covers the medical statements in this post and the sources cited for them.

What is Rick Simpson Oil? How Do You Use RSO?

What Is Rick Simpson Oil?

Who Is Rick Simpson?

RSO Oil vs Cannabis Oil: What’s the Difference?

Claimed Benefits of RSO