The Complete Guide to RSO (Rick Simpson Oil): Uses, Dosing, and Medical Applications

If you have spent any time browsing the shelves of a medical dispensary, you have almost certainly encountered RSO — a dark, thick, tar-like cannabis extract typically sold in oral syringes. Rick Simpson Oil is one of the oldest and most misunderstood products in the modern cannabis market, carrying a history that predates legal dispensaries by more than a decade and a reputation that ranges from miracle cure to dangerous pseudoscience depending on who you ask.

The truth, as usual, sits somewhere in the middle. RSO is a genuinely powerful full-spectrum cannabis extract with legitimate medical applications, but it requires careful dosing, realistic expectations, and an understanding of what it actually is. This guide covers all of it.

What Is RSO?

Rick Simpson Oil is a full-spectrum cannabis extract made by soaking cannabis flower in a solvent — traditionally grain alcohol or isopropyl alcohol — then evaporating the solvent to leave behind a concentrated oil. The result is an extremely potent extract that retains the full range of cannabinoids, terpenes, and other plant compounds present in the original flower.

Unlike distillate, which isolates specific cannabinoids through fractional distillation, RSO preserves the chemical complexity of the plant. A typical RSO syringe contains THC concentrations between 60% and 90%, along with meaningful amounts of CBD, CBN, CBC, and dozens of terpenes. This chemical diversity is what proponents mean when they describe the “entourage effect” — the theory that cannabis compounds work synergistically and that whole-plant extracts produce different therapeutic outcomes than isolated cannabinoids.

The oil gets its name from Rick Simpson, a Canadian who claims to have treated his own skin cancer with a homemade cannabis extract in 2003. Simpson was not a scientist or medical professional, and his specific claims about curing cancer remain unproven in clinical settings. However, the extraction method he popularized produced a genuinely useful product that the medical cannabis community has since adopted and refined.

How RSO Is Made

Traditional RSO production follows a relatively simple process:

1. Solvent Wash: Dried cannabis flower is submerged in a solvent — ethanol is the most common in modern commercial production. The solvent dissolves the cannabinoids, terpenes, and other extractable compounds from the plant material.

2. Filtration: The plant material is strained out, leaving a cannabinoid-rich solvent solution.

3. Evaporation: The solvent is carefully evaporated using low heat, leaving behind a thick, dark oil. Commercial producers use rotary evaporators and vacuum ovens to ensure complete solvent removal.

4. Testing: In regulated markets, the finished RSO is lab-tested for cannabinoid content, residual solvents, pesticides, and microbial contamination.

The dark color of RSO comes from chlorophyll and other plant pigments that are co-extracted with the cannabinoids. Some producers use winterization — a secondary filtration process using cold temperatures — to remove some of these compounds, producing a slightly lighter oil, though purists argue this reduces the full-spectrum benefits.

A critical safety note: While the process sounds simple, home production of RSO involves working with flammable solvents and carries real risk of fire, explosion, and solvent contamination. Commercial RSO from licensed producers is tested for residual solvents. Homemade RSO is not.

Medical Applications

RSO has found legitimate medical applications across several conditions, though it is important to distinguish between anecdotal reports and clinical evidence.

Conditions With Supporting Evidence

Chronic Pain: Full-spectrum cannabis extracts like RSO have the strongest evidence base for chronic pain management. The combination of THC, CBD, and terpenes like myrcene and beta-caryophyllene provides multi-pathway pain relief that isolated cannabinoids often cannot match. If you are exploring cannabis options for pain, our guide to the best strains for anxiety covers strains that also offer pain-relieving properties.

Chemotherapy Side Effects: RSO is widely used by cancer patients for nausea, appetite stimulation, and pain management during chemotherapy. Multiple clinical trials support cannabinoid therapy for these symptoms.

Insomnia: The sedating effects of high-THC full-spectrum extracts make RSO effective for sleep initiation. The relationship between cannabis and sleep is complex — our article on cannabis and dreams explores the science of how cannabinoids affect sleep architecture.

Appetite Stimulation: For patients with wasting conditions, HIV/AIDS, or eating disorders, RSO’s potent THC content reliably stimulates appetite.

Claims With Limited Evidence

Cancer Treatment: While preclinical research shows cannabinoids can kill certain cancer cells in laboratory settings, there are no completed human clinical trials demonstrating that RSO cures cancer. Patients should never substitute RSO for proven cancer treatments without medical supervision.

Epilepsy: CBD-dominant extracts have strong evidence for certain epilepsy syndromes, but THC-dominant RSO is a different product with different risk profiles for seizure patients.

The RSO Dosing Protocol

RSO is extraordinarily potent, and the single most common mistake new users make is taking too much. The standard dosing protocol — often called the “Rick Simpson Protocol” — involves a gradual 90-day ramp-up:

Weeks 1-2: Micro-Dosing Phase

Start with a dose roughly the size of half a grain of rice — approximately 5-10 mg of THC. Take this dose two to three times per day. At this level, most people experience minimal psychoactive effects but begin building tolerance.

Weeks 3-5: Building Phase

Gradually double your dose every four to seven days. Listen to your body. If a dose increase causes uncomfortable psychoactive effects, hold at the current dose for an additional week before increasing.

Weeks 5-12: Therapeutic Phase

Continue increasing until you reach your therapeutic target. The original Simpson protocol aims for 1 gram of RSO per day (approximately 600-900 mg THC), though many medical patients find relief at much lower doses.

Practical Dosing Tips

• Take RSO with fatty food: Cannabinoids are fat-soluble. Taking RSO with a meal containing healthy fats dramatically improves bioavailability and produces more consistent effects.
• Place under the tongue for faster onset: Sublingual absorption bypasses first-pass liver metabolism, producing effects in 15-30 minutes rather than the 60-90 minutes typical of oral ingestion.
• Keep a dosing journal: Track your dose, timing, food intake, and effects. This data is invaluable for finding your optimal dose.
• Start low on days off: If you are new to RSO, begin your dosing protocol on a day when you have no obligations. Even small doses can produce unexpected effects in cannabis-naive individuals.

How to Use RSO

RSO is versatile in its consumption methods:

Oral Ingestion: The most common method. Dispense onto a small piece of food — a cracker, a piece of chocolate, or a spoonful of peanut butter — and swallow. Effects onset in 60-90 minutes and can last 4-8 hours.

Sublingual: Place the oil directly under your tongue and hold for 60-90 seconds before swallowing. Faster onset but shorter duration.

Topical Application: RSO can be applied directly to skin for localized conditions. Mix with coconut oil for easier spreading. Topical application does not produce psychoactive effects.

Capsules: Many patients fill empty gelatin capsules with measured RSO doses for precise, convenient dosing.

Edible Infusion: RSO is already decarboxylated (the heat during extraction activates the cannabinoids), so it can be added directly to recipes without additional preparation. For those interested in cannabis-infused beverages, our cannabis cocktail and mocktail guide offers creative options.

Buying RSO: What to Look For

When purchasing RSO from a dispensary, prioritize these factors:

Full Lab Results: Insist on seeing a certificate of analysis showing cannabinoid profile, terpene content, residual solvent testing, and contaminant screening.

Indica vs. Sativa Source: RSO made from indica-dominant strains tends to be more sedating and is preferred for sleep and pain. Sativa-dominant RSO may be more appropriate for daytime use and appetite stimulation. Check out our best strains of 2026 for insight into the cultivars driving today’s extracts.

THC:CBD Ratio: Some producers offer balanced RSO with significant CBD content. These products may be better tolerated by sensitive patients and can provide therapeutic benefits with less intense psychoactive effects.

Price: RSO is typically one of the most cost-effective concentrate options in dispensaries, ranging from $25 to $60 per gram depending on the market. Its high potency means a single gram lasts most patients several days to several weeks depending on their dosing level.

The Bottom Line

RSO occupies a unique position in the cannabis market — it is simultaneously one of the simplest and most complex products available. Simple because it is a straightforward whole-plant extract. Complex because its full-spectrum chemistry produces effects that vary significantly based on the source material, the patient’s biology, and the dosing approach.

For medical patients willing to invest the time in careful dose titration, RSO offers potent, cost-effective relief for a range of conditions. For recreational users accustomed to vaping or smoking, RSO’s oral bioavailability and extended duration represent a fundamentally different cannabis experience that requires respect and patience.

Start low. Go slow. Keep notes. And consult with a knowledgeable dispensary pharmacist or cannabis-friendly physician who can help you navigate the process safely.