FSO and RSO are two terms you’ll often encounter when researching cannabis extracts. Although they have similarities, they are not necessarily the same thing.
FSO generally means Full-Spectrum Oil. It is a broad description for an extract intended to retain a range of naturally occurring cannabis compounds, potentially including cannabinoids, terpenes and other plant constituents.
RSO, or Rick Simpson Oil, refers to a particular style of cannabis extract associated with Rick Simpson and traditionally characterised as a concentrated, full-plant extract. Products sold under the RSO name can vary considerably in their cannabinoid content, extraction method and formulation.
That distinction is important because “full-spectrum” describes the composition or intended character of an extract, whereas “RSO” describes a particular type or style of cannabis oil.
FSO stands for Full-Spectrum Oil.
The term generally refers to an oil extract designed to retain a broad range of compounds naturally present in the source plant rather than isolating a single cannabinoid.
Depending on the source material and manufacturing process, a full-spectrum extract may contain cannabinoids such as:
It may also contain naturally occurring terpenes and other plant compounds.
However, FSO is not a single standardised formula. Two products labelled “full-spectrum oil” can have very different cannabinoid profiles.
One may be predominantly CBD, while another may contain substantially more THC. The only reliable way to understand an individual product is to examine its product specifications and, where available, independent laboratory testing.
This is why the term full-spectrum should not automatically be interpreted as meaning high-THC, highly concentrated or medicinal.
The name comes from Rick Simpson, a Canadian who popularised a particular style of concentrated cannabis oil and promoted its use through his own experiences.
RSO is commonly described as a thick, dark, concentrated cannabis extract containing multiple naturally occurring cannabis compounds.
Traditionally, RSO has been associated with relatively high THC concentrations. However, products marketed as RSO today can differ substantially from one another.
Factors such as the cannabis variety, extraction process, refinement, formulation and manufacturing standards can all affect the final product.
Therefore, it is better to look at the actual cannabinoid content and laboratory results rather than assuming that every product labelled RSO has the same strength.
| Feature | RSO | FSO |
|---|---|---|
| Meaning | Rick Simpson Oil | Full-Spectrum Oil |
| Type of term | Refers to a particular style of cannabis extract | Describes a broad category of extract |
| Cannabinoid profile | Often associated with higher THC concentrations | Can be CBD-dominant, THC-dominant or balanced |
| Plant compounds | Traditionally retains a broad range of plant compounds | Intended to retain a broad range of naturally occurring compounds |
| Consistency | Can vary between manufacturers | Can vary significantly between products |
| Extraction method | Traditionally associated with solvent-based extraction | May use different extraction methods |
| Appearance | Often thick and dark | Varies considerably |
| Product format | Often sold as concentrated oil | May be sold as oil, tincture or other formulations |
The key point is simple: RSO can be full-spectrum, but not every full-spectrum oil is RSO.
Extraction methods can have a significant effect on the final characteristics of an oil.
Full-spectrum products may be manufactured using different extraction technologies, depending on the producer and intended formulation.
These can include methods involving:
Traditional RSO production is particularly associated with solvent extraction.
The important consideration for consumers isn’t simply the name of the extraction method. Manufacturing controls, purification, residual-solvent testing, cannabinoid analysis and overall product quality are also important.
A professional product should have clear information about its contents and manufacturing standards where applicable.
One of the biggest differences is that FSO is a category, while RSO is a more specific product name.
For example, a full-spectrum oil could contain a predominantly CBD cannabinoid profile with smaller amounts of other cannabinoids.
Another full-spectrum product could contain substantially more THC.
RSO is traditionally associated with a THC-rich cannabinoid profile, but consumers should still check the laboratory results of the specific product rather than relying solely on the RSO label.
