Cannabis RSO oil is a thick, dark extract made by soaking cannabis plant material in a solvent such as ethanol or isopropyl alcohol, then evaporating that solvent to leave a concentrated resin. The name comes from Rick Simpson, who popularized the method in the early 2000s. RSO holds the plant's full range of compounds, including THC, CBD, other cannabinoids, and terpenes.
What is cannabis RSO oil made of?
Most RSO is THC-dominant because it is made from whole cannabis flower rather than hemp. The extract carries cannabinoids, terpenes, waxes, and chlorophyll, which give it a dark green or black color and a bitter taste. Because it is a full-spectrum product, the cannabinoids and terpenes stay together instead of being isolated.
- Cannabinoids: THC and CBD in the ratios found in the starting plant, plus minor compounds like CBG and CBN.
- Terpenes: aromatic compounds such as myrcene, limonene, and pinene.
- Waxes and lipids: plant fats that survive a simple solvent wash.
- Trace solvent: any alcohol left behind depends on how well the extract was purged.
Not every recipe decarboxylates the oil, but most makers use heat to convert THCA into active THC. That step changes the effects, so the process matters as much as the plant material.
How is RSO oil made?
The process is simple in principle and easy to get wrong in practice. Solvents are flammable, and home production carries real risk. Commercial makers work in closed systems with ventilation, grounding, and temperature control.
- Decarboxylate the dried cannabis with heat to activate THC and CBD.
- Soak the plant material in a solvent, often ethanol, for a short window.
- Strain out plant solids and collect the liquid.
- Evaporate the solvent with low heat or a vacuum purge.
- Keep going until the residue becomes a thick oil that does not flow at room temperature.
Short washes pull fewer waxes and less chlorophyll, which gives a cleaner oil. Long washes pull more color and plant matter. The final texture ranges from sap to a waxy solid, depending on the strain and the purge.
How does RSO compare to CBD oil?
RSO and CBD oil sit at opposite ends of the cannabis market. CBD oil sold online is made from hemp, carries 0.3% THC or less under federal law, and comes in measured dropper bottles. RSO comes from marijuana, holds high THC, and ships as a thick resin with no standard dose.
- Source: RSO from marijuana flower, CBD oil from hemp.
- THC content: RSO can reach 60% to 90% THC, while hemp CBD oil stays at or below 0.3%.
- Texture: RSO is a sticky paste, CBD oil is a liquid.
- Dosing: CBD oil has marked droppers, RSO is measured by weight or by a grain of rice.
- Legal status: hemp CBD is legal under federal law, RSO is legal only in states with medical or adult-use programs.
How do people use cannabis RSO oil?
Most people take RSO by mouth or rub it into the skin. Oral use starts with a dose the size of a grain of rice, since THC effects can be strong and slow to appear. Topical use does not produce a high in most cases because THC absorbs through skin at a low rate.
A few practical points matter for oral use:
- Eat something first. THC absorbs better with food and hits with less of a spike.
- Wait two hours before taking more. Effects can take that long to peak.
- Keep it away from heat. RSO softens and sticks to whatever it touches.
Do not vape or smoke RSO. It is not purged for inhalation, and leftover solvent or plant waxes can irritate the lungs. It is also far too thick for most vape hardware.
Is cannabis RSO oil legal in the US?
RSO made from marijuana is illegal under federal law, though many states allow it through medical or adult-use programs. Hemp-derived extracts with 0.3% THC or less are legal under federal law after the 2018 Farm Bill. That means a product labeled RSO sold online is either hemp-derived or sold in a state-licensed market.
Check your state rules before buying. Some states require a medical card for high-THC products. Others cap the THC in any product sold at retail.
What should you check before buying RSO or any cannabis oil?
Lab testing separates a safe product from a risky one. A certificate of analysis (COA) from an independent lab should list cannabinoid potency and test for solvents, pesticides, heavy metals, and mold. If a seller cannot show a COA with a batch number that matches your product, walk away.
- Potency: total THC and CBD percentages.
- Residual solvents: the key test for any solvent-based extract.
- Pesticides and heavy metals: contaminants that concentrate during extraction.
- Microbials: mold and bacteria counts.
- Batch match: the COA number must match the label on the package.
Hemp CBD shoppers should ask the same questions. A report from a third-party lab is the only way to know what a bottle holds.
Side effects and safety
THC is psychoactive, so RSO can cause anxiety, racing thoughts, dry mouth, red eyes, and poor coordination. High doses can bring nausea, paranoia, and a fast heartbeat. These effects pass, but they can feel intense for a few hours.
RSO interacts with the same liver enzymes as some prescription drugs, including blood thinners and seizure medicines. Anyone taking daily medication should talk to a pharmacist or doctor before starting. People who are pregnant, nursing, or under 21 should not use it.
Claims that RSO cures cancer are not supported by clinical trials. Early lab studies and patient reports exist, but research in humans is limited. Treat RSO as a cannabis product, not a proven treatment.
Frequently asked questions about cannabis RSO oil
Does RSO oil get you high?
Yes, if it comes from marijuana. THC content runs from 60% to 90% in most tested samples, and oral doses produce strong effects. Hemp-derived RSO with 0.3% THC or less will not produce a high.
How long does RSO oil last?
Stored in a cool, dark place in a sealed glass jar, RSO keeps for six months to a year. Heat, light, and air degrade THC and terpenes over time.
Can I make RSO at home?
You can, but the process uses flammable solvents and open heat. Most people should buy from a licensed maker with lab tests instead.
Is RSO the same as hash oil or distillate?
No. Hash oil and distillate are refined for vaping, and distillate holds isolated cannabinoids with no terpenes. RSO keeps plant waxes and the full terpene profile.