What Is RSO and Why Is This Full Spectrum Cannabis Oil Different?

RSO stands for Rick Simpson Oil, named after the Canadian guy who popularized a specific method of making ultra-concentrated cannabis extract back in the early 2000s. The key difference between RSO and other cannabis concentrates? It’s a full spectrum cannabis product, meaning it contains the complete range of cannabinoids, terpenes, and plant compounds — not just isolated THC.

Most RSO you’ll find at a medical dispensary in Washington DC is thick, dark, and comes in an oral syringe. It looks like motor oil. That dark color isn’t a quality issue — it’s because the extraction process pulls everything from the plant: THC, CBD, CBN, myrcene, caryophyllene, linalool, all of it. That’s what makes it “full spectrum” and that’s what makes it powerful.

Here’s the thing: RSO isn’t meant for smoking or dabbing. The extraction process doesn’t remove all plant material the way distillate does, so it’s designed for oral consumption — either swallowed directly, mixed into food, or applied sublingually (under your tongue). A lot of people confuse RSO with regular cannabis oil vape cartridges or even cannabis tinctures. They’re fundamentally different products with different onset times, different durations, and wildly different potency levels.

A typical RSO syringe runs 60-80% THC, sometimes higher. Compare that to high THC flower at maybe 25-30%, or a standard edible at 10mg per piece. We’re talking about a cannabis concentrate that demands respect and patience — especially if you’re new to it.

Cannabis Decarboxylation: Why RSO Works When You Eat It

This is the part most people skip, and it’s the part that actually matters. Raw cannabis doesn’t get you high. The THC in a living plant exists as THCA — an acidic precursor that your body processes very differently. Cannabis decarboxylation is the chemical reaction that converts THCA into active THC through heat.

When you smoke flower or use a vape, decarboxylation happens instantly from the flame or heating element. But when you eat cannabis, it needs to be decarboxylated before consumption. This is why eating raw bud doesn’t do anything useful (no judgment, everyone asks). RSO is already fully decarboxylated during its extraction process, which is why it works immediately when ingested. That’s a huge advantage over trying to make your own edibles at home, where inconsistent decarboxylation is the number one reason people’s homemade brownies either don’t work at all or send them to the moon.

Cannabis bioavailability — meaning how much THC your body actually absorbs — changes dramatically based on how you consume it. Sublingual cannabis absorption is faster than swallowing, usually kicking in within 15-30 minutes because the oil absorbs through the blood vessels under your tongue. Swallowing RSO means it goes through your digestive system first, which takes 45 minutes to 2 hours but often hits harder and lasts longer. Understanding this difference is the key to dosing correctly.

How to Dose RSO: A Practical Guide for Medical Cannabis DC Patients

Alright, this is where I get really specific, because “start low and go slow” is true but not particularly helpful by itself. Here’s how I actually walk patients through their first RSO experience at our shop on Connecticut Avenue.

Step 1: Start with a rice grain. Seriously. Squeeze out a piece of RSO about the size of a single grain of rice. That’s roughly 10-25mg of THC depending on the product’s potency. If you’ve never used RSO or you’re new to edibles entirely, this is your starting point. Put it on a small piece of food — a cracker, a spoonful of peanut butter, whatever — and eat it.

Step 2: Wait at least two hours. The most common mistake I see with RSO is impatience. People take a dose, feel nothing after 45 minutes, take more, and then three hours later they’re calling us asking if they’re going to be okay. (Yes, you’ll be fine, but it won’t be fun.) Two hours. Set a timer. Don’t redose before then.

Step 3: Increase gradually. If that rice grain wasn’t enough, add another rice grain to your next dose. Not double. Not triple. One more grain. Learning how to dose edibles is a slow process because everyone’s endocannabinoid system responds differently.

For sublingual use, place the RSO under your tongue and hold it there for 60-90 seconds before swallowing. You’ll feel effects sooner this way (seriously, sometimes 15 minutes), but for some patients the taste is intense. Mixing it into a warm drink can help, though that converts your sublingual dose into an oral one with a longer onset.

A lot of the medical cannabis patients I work with in DC — especially those dealing with cannabis and chronic pain issues — eventually find their sweet spot somewhere between a rice grain and a pea-sized amount, taken once or twice daily. Some patients with more severe conditions work up to much higher doses over weeks or months, but that’s a personal journey you should be tracking in a journal.

What Forms of Cannabis Are Sold in DC — And Where RSO Fits

If you’re wondering what forms of cannabis are sold in DC, the answer is: most of them. Flower, pre-rolls, vape cartridges, edibles, tinctures, topicals, and concentrates including RSO are all available at licensed dispensaries. The variety can be overwhelming, and I think that’s part of why people sleep on RSO — it doesn’t look as approachable as a gummy or a pre-roll.

But here’s where RSO fills a gap that other products can’t. A cannabis tincture is great for mild-to-moderate symptom management and precise dosing, especially if you want to know exactly how many milligrams you’re taking per dropper. Tinctures are usually alcohol or MCT oil-based, and most of our patients from the U Street Corridor and Logan Circle areas use them for daily maintenance. They’re predictable and easy. If you’re curious about how to take a cannabis tincture, check our cannabis FAQ — we’ve got a whole breakdown there.

RSO, though, is for when you need more. More potency, more cannabinoids working together, more duration. The entourage effect — all those cannabinoids and terpenes like pinene, limonene, and caryophyllene working in concert — is strongest in full spectrum products like RSO. That’s why patients managing serious chronic pain, appetite loss, insomnia, or nausea often end up here after other products didn’t quite cut it.

You can also use RSO to make your own edibles at home with precise dosing. Since it’s already decarboxylated, you just stir it into melted butter, coconut oil, or any fatty base. No oven decarb step needed. This is genuinely one of the easiest ways to make consistent homemade edibles, and I recommend it over the “grind flower and bake it” method every single time.

Getting Your DC Health Cannabis Registration — It Takes About 2 Minutes

Honestly, the hardest part of becoming a medical cannabis patient in DC is believing how easy it actually is. There’s no doctor’s appointment required. No fee. No waiting room. DC uses a self-certification process, and it’s all done online through the DC Health medical cannabis program.

Here’s the breakdown:

• You must be 21 or older
• Go to the DC Health website and self-certify — you’re essentially stating that you have a qualifying condition
• The whole process takes about two minutes (seriously, two minutes)
• There’s no cost to register
• No doctor visit, no medical records, no hoops

The question I hear most often — from federal employees in Dupont Circle, from contractors in Shaw, from literally everyone who works near a government building — is: “Will my employer find out?” The answer is no. The ABCA (DC cannabis regulator) enforces strict patient privacy rules. Your registration data isn’t shared with employers, federal agencies, or anyone else. Period. You’re protected. There’s zero career risk from getting your DC Health cannabis registration.

Once you’re registered as a medical cannabis patient in DC, you can purchase from any licensed dispensary in the district — including us at MrGreen DC dispensary on Connecticut Avenue. You’ll have access to RSO, tinctures, flower, edibles, and every other product form we carry. Browse our cannabis menu to see what’s currently in stock.

Ready to Try RSO? Come Talk to Us.

If you’ve read this far, you’re already more informed about cannabis oil than most patients who walk through our door — and that’s a great place to be. RSO isn’t complicated once someone actually explains it, but it’s also not something you should guess your way through alone. Whether you’re in Columbia Heights, Adams Morgan, or anywhere else in the district, we’re here to help you figure out the right product, the right dose, and the right consumption method for your situation. Stop by our store on Connecticut Avenue NW, or if you’d rather stay home, we offer same-day weed delivery across DC. You’ve got questions — we’ve got six years of answers and a shelf full of cannabis oil ready to go.