RSO / FECO (Rick Simpson Oil)
Highly concentrated full-spectrum cannabis extract in an oral syringe. Extremely potent. For experienced patients under physician guidance.
Onset
30-120 min (oral), 15-45 min (sublingual)
Duration
4-8+ hours
Dosing Control
medium
Discretion
High
Difficulty
intermediate
What It Is
RSO (Rick Simpson Oil) and FECO (Full Extract Cannabis Oil) are highly concentrated, full-spectrum cannabis extracts typically dispensed in a 1-gram oral syringe with a plunger for controlled dispensing. The extract is dark brown to black in color, thick, tar-like, and sticky. It contains the full range of cannabinoids (THC, CBD, CBN, CBG, and others), terpenes, flavonoids, and additional plant compounds extracted together, which proponents believe produces a stronger "entourage effect" than isolated cannabinoid products.
RSO is named after Rick Simpson, a Canadian cannabis activist who popularized the oil in the early 2000s for cancer treatment. It is important to note that cannabis, including RSO, is NOT an FDA-approved cancer treatment. However, RSO has become one of the most sought-after products among medical cannabis patients dealing with severe symptoms, particularly cancer-related pain, nausea, appetite loss, and the side effects of chemotherapy. For patients with conditions requiring high-dose cannabis therapy, RSO offers the most concentrated oral option available: a single gram syringe typically contains 500-900mg of THC, making it far more potent per volume than any edible, tincture, or capsule.
RSO is widely available in most medical cannabis programs with full product menus. It is relatively affordable on a cost-per-milligram-of-THC basis compared to other products, which matters for patients who require large daily doses. The trade-offs are that RSO is extremely potent (making accurate dosing critical), has an unpleasant taste (bitter, plant-like, medicinal), and is thick and sticky, making it difficult to dispense precisely from the syringe without practice.
How It Works
RSO can be consumed through multiple routes of administration, each with different onset times, durations, and effects:
Oral (Swallowed) Method:
1. Warm the syringe between your hands for 20-30 seconds. RSO is very thick at room temperature and flows much more easily when slightly warmed.
2. Dispense a rice-grain-sized amount (approximately 5-10mg THC for beginners) onto a small piece of food: a cracker, a piece of bread, a banana slice, or a peanut butter ball. The food serves two purposes: it masks the strong, bitter taste, and the fat content in the food can improve cannabinoid absorption.
3. Swallow the food with the RSO. Do not chew or try to taste the oil.
4. When swallowed, RSO is processed through the digestive system and metabolized by the liver, just like any standard edible. The liver converts THC to 11-hydroxy-THC, which crosses the blood-brain barrier more readily and produces stronger, longer-lasting psychoactive effects than inhaled THC.
5. Onset is 30-120 minutes. Effects last 4-8+ hours, sometimes longer at higher doses.
Sublingual Method:
1. Dispense a small amount directly under the tongue or along the gum line.
2. Hold for 60-90 seconds to allow absorption through the mucous membranes before swallowing.
3. Sublingual absorption bypasses the liver for the initial dose, providing faster onset (15-45 minutes) with a secondary wave of effects when the swallowed portion is processed orally.
Other Administration Routes: RSO can be loaded into empty gel capsules for tasteless, precise oral dosing. It can be applied topically to skin conditions (though purpose-made topicals are usually more practical). It can also be used in suppositories for patients who cannot take medications orally, such as those experiencing severe nausea or undergoing certain treatments.
The "Rick Simpson Protocol" commonly circulated online recommends gradually increasing to 1 gram per day (500-900mg THC daily). This protocol is NOT medically validated and represents an extremely high dose. Patients should work with their physician to determine an appropriate dose based on their condition, tolerance, and other medications.
Types and Variations
RSO vs FECO:
RSO (Rick Simpson Oil) and FECO (Full Extract Cannabis Oil) are functionally the same product: a full-spectrum, whole-plant extract. The names are used interchangeably by most dispensaries. Some producers prefer "FECO" as a more clinically neutral term, while "RSO" carries name recognition among patients. The extraction process may differ slightly between producers (ethanol vs CO2 extraction), but the end result is a concentrated, full-spectrum oil.
THC-Dominant RSO:
The most common formulation. Contains 50-90% THC with the full complement of minor cannabinoids and terpenes from the source plant. Used for severe pain, nausea, appetite stimulation, insomnia, and other conditions requiring potent THC therapy. Most patients use THC-dominant RSO.
CBD-Dominant RSO:
Contains high concentrations of CBD with minimal THC (typically below psychoactive thresholds). Used for patients who want the full-spectrum entourage effect of a whole-plant extract without significant psychoactivity. Applied for inflammation, anxiety, seizure management, and other conditions responsive to CBD.
Balanced Ratio RSO:
1:1 THC:CBD formulations that provide both cannabinoids in equal proportion. The CBD moderates the psychoactive intensity of the THC while both contribute therapeutic effects. Often recommended by physicians as a starting point for patients new to RSO.
Strain-Specific RSO:
Some producers offer RSO made from specific cannabis cultivars (strains), preserving the unique cannabinoid and terpene profile of that strain. Indica-dominant RSO is commonly marketed for sleep and pain, while sativa-dominant RSO is marketed for daytime use and mood. The clinical significance of strain specificity in RSO is debated.
Packaging:
RSO is almost universally dispensed in 1-gram oral syringes with graduation markings for dosing. Some dispensaries sell multi-packs or larger syringes. The syringe format allows patients to dispense small, controlled amounts, though the thick consistency still makes precise dosing challenging without warming the syringe first.
Clinical Reference
| Onset | 30-120 min (oral), 15-45 min (sublingual) |
| Duration | 4-8+ hours |
| Bioavailability | Variable (oral 4-20%, sublingual 20-35%) |
| Dosing Control | medium |
| Difficulty | Intermediate |
| Psychoactive | yes |
Dosing Guide
CRITICAL: RSO is extremely potent. Start here regardless of other cannabis experience.
Slowly build tolerance. Do not rush. Listen to your body.
Most patients find their maintenance dose well below the aggressive "Rick Simpson Protocol." Always physician-guided.
Pros and Cons
Pros
- Most potent oral cannabis product available: 500-900mg THC per 1-gram syringe, providing maximum therapeutic intensity for severe symptoms
- Full-spectrum whole-plant extract preserves the complete cannabinoid, terpene, and flavonoid profile, maximizing the entourage effect
- Very cost-effective per milligram of THC compared to edibles, tinctures, or capsules, which matters for patients requiring large daily doses
- Versatile administration: can be swallowed on food, taken sublingually, loaded into capsules, applied topically, or used in suppositories
- Small volume needed: a single rice-grain-sized dose delivers significant therapeutic effects, and one 1g syringe can last a moderate-dose patient weeks
- Widely available in most medical cannabis programs with full product menus
- No smoking, vaping, or inhalation required, making RSO suitable for patients with respiratory concerns
Cons
- Extremely potent: improper dosing can cause severe discomfort (anxiety, paranoia, nausea, sedation) lasting many hours with no way to accelerate the process
- Unpleasant taste: RSO has a strong, bitter, plant-like flavor that most patients find disagreeable and must be masked with food
- Difficult to dose precisely due to the thick, sticky, tar-like consistency that resists smooth dispensing from the syringe
- Thick consistency makes dispensing and handling messy, especially in cold temperatures when the oil becomes even thicker
- Not beginner-friendly: the extreme potency and difficult dosing make RSO inappropriate for new cannabis patients without physician guidance
- Slow onset when swallowed (30-120 minutes), making it difficult to titrate effectively in a single session
- The "Rick Simpson Protocol" (aggressive online dosing recommendations) can mislead patients into dangerously high doses without medical supervision
Who Is This Best For?
Best For
- Patients with severe symptoms
- Patients with high tolerance
- Cancer patients (symptom management)
- Patients with chronic pain requiring high doses
- Always under physician guidance
Not Recommended For
- New cannabis patients
- Patients without physician oversight
- Anyone uncomfortable with high-potency products
Patient Tips
- Warm the syringe between your hands for 20-30 seconds before dispensing. RSO flows much more smoothly when slightly warmed. Some patients briefly run warm (not hot) water over the capped syringe to soften the oil.
- Place your dose on a small piece of bread, cracker, banana, or in a peanut butter ball to mask the strong, bitter taste. The fat content in these foods also improves cannabinoid absorption.
- Keep a detailed dosing journal: date, time, amount dispensed, route of administration, onset time, effects, and duration. RSO dosing is highly individual and a journal is the most reliable way to find your optimal dose.
- Start with a rice-grain-sized amount (approximately 5-10mg THC) regardless of your prior cannabis experience. RSO is dramatically more concentrated than other oral products, and the standard beginner edible dose of 2.5-5mg can easily be exceeded with a slightly larger dispense.
- Store RSO in a cool, dark place. Refrigeration extends shelf life and can make the oil thicker (use the warming technique before dispensing). Avoid storing in direct sunlight or heat, which can degrade cannabinoids over time.
- The "Rick Simpson Protocol" recommending 1g per day (500-900mg THC) circulates widely online but is NOT medically validated. This represents an extreme dose. Work with your physician to determine an appropriate dose for your specific condition and tolerance.
- If you find syringe dosing too imprecise, load RSO into empty gel capsules (available at any pharmacy) for consistent, pre-portioned doses. This also completely eliminates the taste issue.
Safety Information
RSO is 50-90% THC. A full 1g syringe contains 500-900mg THC. For context, a beginner edible dose is 2.5-5mg. Overdosing is not fatal but can cause extreme discomfort (anxiety, paranoia, nausea) lasting many hours. ALWAYS start with the smallest possible amount. The Rick Simpson Protocol is popular online but NOT medically validated. Never attempt aggressive dosing without physician supervision.
Related Methods
Frequently Asked Questions
What is RSO used for?
RSO is used by medical patients for severe symptom management, particularly cancer-related symptoms (pain, nausea, appetite loss, chemotherapy side effects), chronic pain requiring high-dose therapy, insomnia, muscle spasms, and other conditions where lower-potency products provide insufficient relief. RSO is NOT an FDA-approved cancer treatment. It is used for symptom management under physician guidance.
How much RSO should a beginner take?
Start with a piece the size of half a grain of rice, approximately 5-10mg THC. Place it on food and swallow. Wait at least 2 hours to assess effects before taking more. RSO is extremely concentrated (50-90% THC per gram, meaning 500-900mg THC in a single syringe). Even experienced cannabis patients who use edibles or flower regularly should start at the lowest possible RSO dose because the concentration is dramatically higher than other oral products.
What is the difference between RSO and a tincture?
RSO is a thick, tar-like full-extract oil with very high potency (50-90% THC per gram) dispensed in a syringe. Tinctures are liquid cannabis extracts dissolved in a carrier oil (MCT, olive, or hemp seed oil) with a measured dropper for precise dosing, typically containing 10-30mg THC per milliliter. Tinctures are much easier to dose accurately and are recommended for most patients. RSO is reserved for patients who need extremely high potency or have exhausted the dosing range of tinctures.
Can I smoke or dab RSO?
No. RSO is not designed for inhalation. It is a full-plant extract that may contain chlorophyll, lipids, and other plant materials that are not safe to inhale. Some RSO products may also contain residual extraction solvents. RSO is intended for oral, sublingual, or topical use only. If you want to inhale concentrates, use products specifically made for that purpose (wax, shatter, live resin) from a licensed dispensary.
How long do RSO effects last?
When swallowed, RSO effects typically last 4-8+ hours, similar to standard edibles but often longer due to the high dose and full-spectrum composition. At higher doses, residual effects (sedation, cognitive fog) can persist for 12+ hours. Sublingual administration produces somewhat shorter but faster-acting effects. Always plan for RSO to last longer than expected, especially when finding your dose.
Is the Rick Simpson Protocol safe?
The Rick Simpson Protocol, which recommends gradually increasing to 1 gram of RSO per day (500-900mg THC daily) over 90 days, is NOT medically validated and is NOT recommended without physician supervision. One gram per day represents an extremely high THC dose. While some patients under medical supervision do use high-dose RSO regimens, the protocol as popularized online lacks clinical evidence and poses significant overconsumption risk. Work with your physician to determine an appropriate, individualized dose.
This content is for educational purposes only and is not a substitute for professional medical advice. Consult with your certifying physician about which consumption method is appropriate for your specific medical condition and treatment plan. Cannabis affects everyone differently based on individual factors including tolerance, metabolism, and medical history. Always start with the lowest effective dose and increase gradually.
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