RSO oil, short for Rick Simpson Oil, is a thick, dark cannabis extract that usually runs 60% to 90% THC. The short answer on how to use it: measure a dose around a quarter of a short grain of rice or less, take it by mouth or under the tongue, wait two full hours before adding more, and keep your day clear. It is not a vape product. It is not a cancer treatment. Anyone who tells you otherwise is selling something.
What you are actually working with
RSO gets made by soaking cannabis plant material in a solvent, then evaporating the solvent off. What is left is a sticky, tar-like oil that holds most of the plant's cannabinoids plus plenty of waxes and chlorophyll. Because it is a full extract and not a distilled concentrate, potency swings from batch to batch. One gram can carry anywhere from 600 to 900 mg of THC. That number is the whole ballgame. A dose you can barely see can still be a real dose.
Pick your route before you pick a dose
Under the tongue
Place the oil under your tongue, hold it there for a minute or two, then swallow. You absorb some THC through the tissue in your mouth, which skips the liver on the first pass. Onset tends to land somewhere between 15 and 45 minutes, and the effect is often a bit shorter and less heavy than swallowing it straight.
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Swallowed
This is the most common way people take RSO, and it is the one that surprises newcomers. Your liver converts THC into 11-hydroxy-THC, a metabolite that is stronger and lasts longer. Onset stretches to 30 to 90 minutes, peak effects show up around two to four hours in, and the whole thing can run six hours or more. If you are new, swallowed is where you learn patience.
On the skin
Rubbing RSO on a sore knee or a scar is a different experience. Absorption through intact skin is limited, so most people get little to no high. It is a reasonable option for localized aches when you do not want to be impaired.
Not in a vape
RSO is not made for inhalation. It contains residual plant waxes, lipids, and whatever solvents the maker did not fully purge. Burning or vaporizing that sends junk into your lungs. Buy lab-tested distillate or live resin if you want to inhale.
Dosing: start lower than the label suggests
I look for the total THC per gram on the label, then do the math backward. If a gram tests at 700 mg THC and you want a 5 mg dose, you need roughly 7 mg of oil, which is a smear smaller than most people expect. A typical 1 mL syringe holds about 1 gram, so the markings on the barrel are your measuring tool. A first dose of 2.5 to 5 mg THC is plenty for most adults.
- Take your first dose at home, on a day with nothing on the calendar.
- Wait a full two hours before deciding it did not work.
- Raise the dose in small steps, and only every few days, not every few hours.
- Keep a short note of dose, time, and how you felt. Memory is a poor record keeper here.
- Ignore any dosing schedule you read online that jumps straight to hundreds of milligrams. Tolerance and body weight matter, but nobody needs to start there.
What the first few hours feel like
Expect dry mouth, heavy eyelids, and a body buzz that builds in waves rather than hitting all at once. Some people get sleepy. Some get chatty. Some get anxious, and that usually passes once the peak does. Lying down, drinking water, and eating something can take the edge off. Chewing black peppercorns is a folk remedy, not a rescue, so give it time instead.
Things to avoid
- Alcohol, benzodiazepines, and opioids. They stack with THC and can slow your breathing.
- Driving or operating anything until you know exactly how the dose treats you. That can take a few sessions.
- Taking a second dose because the first one felt mild at the 45 minute mark. That is how bad nights start.
- Buying from anyone who cannot show you a lab test for potency, pesticides, and residual solvents.
Storage and labeling
RSO is sticky and it will glue a cap shut. Keep it in the original glass syringe, sealed, in a cool dark spot, and the fridge is fine if you let it warm to room temperature before dosing. Write the date and the THC percentage on the box. Keep it well out of reach of kids and pets, since a single gram can contain a month of doses for a new user.
When to call a clinician
Talk to your doctor before you start if you take blood thinners, seizure medication, immunosuppressants, or anything with a narrow therapeutic window, because cannabinoids can shift how those drugs get metabolized. Call for help if you get chest pain, a racing heartbeat that will not settle, repeated vomiting, or confusion that does not ease as the high fades. High doses of THC can trigger panic and, in people with a personal or family history of psychosis, something more serious. Medical cannabis is legal in many states and still illegal under federal law, so keep your purchases inside the licensed system and keep the conversation with your care team honest.