Delta-8-tetrahydrocannabinol (D8-THC) was the beginning of a cannabinoid conversion revolution. The promise of a milder, legal, and hemp-derived form of THC was compelling to many. Hemp product manufacturers who lived through the massive drop in cannabidiol (CBD) wholesale price saw D8-THC as a lifeline. Opponents to D8-THC note that most products contain impurities, including delta-9-THC (D9-THC), and that without any testing requirements, it is difficult for the consumer to know what they are purchasing.
More recently, other hemp-derived cannabinoids have hit the market. These include (among others) hexahydrocannabinol (HHC), THC-O-Acetate, and tetrahydrocannabiphorol (THC-P). Each of these converted cannabinoids promise novel therapeutic effects and intoxicating effects that range from mild to several times more psychotropic than D9-THC.
As our collective understanding of these converted cannabinoids continues to grow, the pace of discovery has outpaced testing and regulatory capabilities. Most labs are not yet able to measure converted cannabinoids, and many cannabis and hemp governing bodies simply don’t understand their benefits or risks. This is a temporary problem, though a serious one. People are manufacturing and selling cannabinoid-containing products with little oversight, and bad players can and will take advantage of the situation and sell products claiming to contain converted cannabinoids when in fact they contain something else. False claims and incorrect or inaccurate labeling damages industry progress, can cause the loss of consumer confidence, and even impart physical harm.
Primer on Converted Cannabinoid Manufacturing
Converted cannabinoids generally start with hemp-derived CBD isolate, which is then subjected to various chemical reactions which convert them into their final form. By looking at the manufacturing process of the converted cannabinoids, we can shed some light on what to expect during testing.
HHC is typically made from cannabinol (CBN) in isolate form. The CBN isolate itself is typically extracted and purified from hemp or cannabis plants. The CBN is reacted with hydrogen and a metal catalyst to create HHC. This is a similar process to oil hydrogenation; those guilt-inducing Twinkies contain hydrogenated oils which make them longer lasting and better tasting. Since HHC is usually made from CBN, we should look out for stray CBN in the products which would indicate incomplete reactions.
THC-O-Acetate is created by taking D8-THC or D9-THC and sending it through an “acetylation” process, which adds an acetate functional group to the molecule. This extra functional group allows the THC to become more potent possibly through increased bioavailability. The process requires acetic anhydride, which is an extremely dangerous chemical. In addition, the acetylation process can acetylate other compounds or cannabinoids in the original feedstock, thus making unknown by-products. Just as there can be D8-THC and D9-THC, similarly THC-O-acetate can be D8-THC-O-acetate or D9-THC-O-acetate. Most of the products labeled “THCO” contain D8-THC-O-acetate since they are made from D8-THC as a starting point. Looking for significant amounts of D8-THC would be useful to determine whether the acetylation process was complete. Looking for unknown compounds is important for THC-O-acetate samples since acetylation of unknown compounds may make them more bioavailable and thus dangerous.
Unlike THC-O-acetate and HHC, THC-P cannot be created directly from typical hemp cultivars. This is because most hemp cultivars create a cannabinoid with five atoms in its alkyl side chain. THC-P has a seven-atom alkyl side chain, which requires specific genetics. Only one cultivar has been discovered so far and was found by Italian researchers in 2019.  The only other option is to synthesize the THC-P molecule from scratch using a string of chemical reactions. The latter has potential to make bulk amounts of THC-P but requires extreme expertise, expensive equipment totaling in the millions of dollars, and a healthy appetite for risk due to the dangerous chemicals and reactions required. Due to the cost, this cannabinoid is most likely to be sold without any of the actual active ingredient present. THC-P, much like THC-O-acetate can be either D9-THC-P or D8-THC-P depending on the processes used to create the cannabinoid.
Putting Converted Cannabinoids to the Test
We wanted to find out how pervasive the issue of converted cannabinoid mis-labeling is, so we purchased twelve converted cannabinoid products from various online retailers and put them to the test. Form factors included vape cartridges, gummies, and distillates. We employed a LightLab 3 liquid chromatograph by Orange Photonics to analyze the samples. The LightLab was calibrated with converted cannabinoid reference standards from Cayman Chemical, though it should be noted that the reference standards are not yet “certified” reference materials, so the absolute accuracy cannot be guaranteed. Since these standards are the only ones available to commercial laboratories, we expect the LightLab accuracy to be on par with a commercial lab using the same standards. LightLab uses a combination of liquid chromatography to separate the cannabinoids, and ultraviolet spectroscopy to quantify the amount of each cannabinoid after separation. This process is nearly identical to a laboratory cannabinoid analysis.
Test Results: The Good, the Bad, and the Ugly
The results of the test show that, while some products are labeled exactly as the consumer would expect, others were not so great. Table 1 below shows a summary of what we found split into three product categories: HHC products, THC-O-acetate products, and THC-P products. Overall, an alarming one-third of the samples tested contained no detectable traces of the advertised cannabinoid.
HHC Product Results
We tested a distillate, vape cartridge, and gummy containing HHC. The distillate rang in at an impressive 99+% purity. Clearly the manufacturer knew how to make the product correctly and with few or no impurities. The vape cartridge did contain 26.2% HHC, however it also contained over 30% CBN. That points to an incomplete reaction, which led to lower HHC content than expected. Finally, the HHC gummy we tested contained no trace of HHC whatsoever. It did, however, contain D8-THC. Most likely this gummy product was a D8-THC gummy mislabeled (either intentionally or not) as HHC.
THC-O-Acetate Product Results
Two vape cartridges, a distillate, and two gummies were tested that purported to contain THC-O-acetate. Both vape cartridges contained the cannabinoid in significant quantities, though below the advertised value. Both also contained significant levels of unknown compounds. Finally, both contained small amounts of D9-THC-O-acetate, likely because the original D8-THC starting product contained some D9-THC. The distillate matched the lab report provided and contained no detectable unknown compounds. Finally, one of the gummies tested about 40% higher than expected on THC-O-acetate while the second gummy contained no cannabinoids at all.
THC-P Product Results
Two THC-P vape cartridges and two THC-P distillates were tested. Neither vape cartridge contained any detectable amounts of THC-P. One cartridge seemed to be a typical D8-THC cartridge while the other one was a THC-O-acetate cartridge. This is in some ways unsurprising since this cannabinoid is the hardest to manufacture, so it is the most likely to be faked. The two distillates did contain significant amounts of THC-P. Note the distillates purchased were from a specialty rare-cannabinoid manufacturer and cost ten times more than the vape cartridges. It seems that with THC-P you get what you pay for.
Converted cannabinoids seem to be a double-edged sword for cannabis and hemp producers. On the one hand, they promise new therapeutic and recreational opportunities and a way to make profits in a time when plant-based cannabinoids are slumping in price. However, the lack of regulation and testing are obvious in the test results we obtained on LightLab. A full one-third of the samples didn’t even contain the labeled cannabinoid, while many others failed to match the lab reports or contained unknown and potentially dangerous substances. If this continues, harsh regulations and consumer distrust will degrade the legitimacy of the cannabis industry as a whole.
The best defense against this problem is to weed out the bad players through testing along the supply chain. Manufacturers need to be able to determine whether their conversions were efficient and successful. Wholesalers need to be able to trust their suppliers or risk reputational or legal damages. End product sellers who interface with consumers need to provide accurate information about their products to avoid putting their customers in danger. While testing isn’t free, it’s a worthwhile investment both to the industry as a whole and to an individual company that wants to succeed long term.
Reference Citti C, Linciano P, Russo F, et al. A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ9-tetrahydrocannabinol: Δ9-Tetrahydrocannabiphorol. Sci Rep. 2019;9(1):20335. [journal impact factor = 4.380; times cited = 70]