There’s a buzzword alive-and-well in marketing hemp-based cannabidiol (CBD) rich products; Δ-9-Tetrahydrocannabinol (THC)-free. Industrial hemp is defined by its scant THC content, with the legal threshold in the United States being anywhere below 0.3%. The threshold set by the European Union is slightly lower at 0.2%. Switzerland says hemp should be <1% THC, Thailand says 0-3%, and wet, wild and wonderful West Virginia in the US boldly states <1% THC as well.
The Australian Government’s Office of Drug Control states ‘hemp oil’ is defined as an extract of Cannabis and, for the purpose of the Narcotic Drugs Act 1967 (the Act), an ‘extract of Cannabis’ is any substance obtained by separation of components from a plant in the genus Cannabis. The Act implements the Single Convention on Narcotic Drugs of 1961 (Single Convention) which states an ‘extract of Cannabis’ is a ‘drug’ (wrongly described, however). But, by this incorrect definition, ‘hemp oil’ is also a ‘drug’.
The Single Convention and Australian law are silent on the levels of THC in Cannabis extracts and deems all extracts of Cannabis as ‘drugs’, regardless of specific cannabinoid levels. Therefore, in Australia, ‘hemp oil’ that is deemed a ‘medicinal Cannabis’ product may only be accessed by prescription from a doctor granted Special Access Scheme Approval or has Authorised Prescriber status and may only be imported under a licence and permit to import.
Historically the international definition of hemp was developed by a Canadian researcher, Ernest Small, in 1971. His arbitrary 0.3% THC limit became standard around the world as the official limit for ‘legal’ hemp, after he published The Species Problem in Cannabis. In his book, Small discussed how “there is not any natural point at which the cannabinoid content can be used to distinguish strains of hemp and ‘marijuana’”.
Despite this he continued to “draw an arbitrary line on the continuum of Cannabis types and decided that 0.3% THC in a sifted batch of Cannabis flowers was the difference between hemp and ‘marijuana’”, and this continues to add to the controversy and confusion as to what truly constitutes the difference between Cannabis and hemp.
Across the United States (and other jurisdictions where Cannabis use is legal) there are products that are technically legal to ship across state or country borders, depending on the THC potency. Perhaps to the chagrin of those seeking the entourage effect, many companies are opting for what they’re calling ‘THC-free’, which, like caffeine-free, implies there is 0% of the substance. However, depending on how the product was created, THC-free might not really mean there’s no THC, just like caffeine-free and decaffeinated beverages are not the same. Decaf coffee still contains some caffeine.
A CBD product made with isolate might represent a true THC-free product. A broad-spectrum product that has lots of other phytomolecules like cannabinoids and terpenes requires THC removal, perhaps through a method like supercritical fluid chromatography. What’s important to know, though, is that in cases where the THC has been removed there still might be traces of it present. When a laboratory measures how much THC is in a given sample, they are limited in how low they can accurately quantify.
Labs have limits of detection and quantitation for their methods, and these metrics can vary from lab-to-lab. Additionally, there are gradients in detection technology, such as the use of ultraviolet (UV) detector versus mass spectrometry. The sensitivity of the method changes depending on the sophistication of the detection technology. What this all means is that one lab may not detect THC, while another might employ a different method that does. And while all labs can ensure compliance through measuring the required limits of THC content mentioned above, to say that a product is 100% THC-free could be misleading. One fate of this could be in workplace drug testing.
There have been many stories across North America of prospective employees losing out on a job because they bought a CBD product and tested positive for THC when drug tested. One method used by laboratories performing urinalysis (in the US) typically measures down to 50 nanograms per millilitre (ng/ml). Other thresholds might be 5 to 100 ng/ml, but regardless, these are very small concentrations. Some will measure THC metabolites in hair samples and these tests can often get to even lower quantities such as 1 picogram per millilitre (a picogram is 1/1000 of a nanogram).
Thus it’s important to differentiate between truly THC-free products and those products where the laboratory who provided the certificate of analysis (CoA) just didn’t detect the THC with their validated method on their instrumentation. So be careful when selecting CBD products and note that if you look at the CoA of a product and next to Δ-9-THC, it says n.d., that means not detected and not necessarily free.