CBD May Convert to THC in the Stomach


Chemical conversion of CBD to THC was known to be possible but commercially unfeasible as it was cheaper to grow the THC than convert it. But a 2007 study suggests that stomach acid can convert oral CBD to Δ9 THC (2.9%), CBN (1.1%), and two metabolites (1.4% and 10%), one of which is 25% as stony as Δ9 THC. It is a highly significant finding for CBD therapy and product development.

The ramifications for patients: if you have to be drug tested or not-high at work then consider alternative delivery systems such as transdermal patches, sublingual tinctures, vaping, smoking flowers (Nobacco), or suppositories. Also, if you are taking 50 mg of CBD orally other than sublingually, it means you are really getting no more than 85% as much as you think, and may want to consider an alternative delivery source. (It also explains why you may have felt high on just oral CBD.)

For product developers, you’ll want to consider controlled release, agglomerating with a gel (carrageenan is used but hempseed protein can also make films), microencapsulation or buffering. Food product developers need to assess the risk of drug test interference resulting from over-zealous consumption of a product containing 50 mg CBD per serving: will 500 mg of CBD in your too-delicious cookie converting to 14.5 mg THC and 5.5 mg CBN cause a drug test positive for him or her at work? (But remember: cannabinoids in foods are implicitly allowed by the FDA and state health departments, and DEA is permanently enjoined from enforcing the Controlled Substances Act on hemp cannabinoids. There is even an entire website with dozens of food and supplement manufacturers proudly declaring to the public that their products actually contain undisclosed and undeclared THC, sometimes enough to cause a DUID.)

Besides negatively confusing CBD edibles with THC edibles (already a bigger market in just Colorado than all the edible hemp products imported from Canada), it is also possible consumers will eventually come to associate CBD with becoming THC in their stomach, and/or realize that there can be a significant amount of THC in hempseed oil already. (Thereby highlighting the need for hemp and CBD advocates to cease demonizing and start affirming the healing and neuroprotectant properties of nonpsychoactive micro-doses of THC, especially to legislators. Eventually we’re going to ask them for 1% THC so we can use feral hemp, so you might as well get them used to the idea. We now have the momentum, 89% of the people support THC for medical and 54% support recreational marijuana, so in reality there is no there’s no political, moral, or re-election downside, it only exists between the ears of the “baby-steppers” slowing us down.)

For hemp policy wonks, now possibly “CBD = THC” which means “Hemp = THC” and the resulting consequences, such as:

  • a THC DUID from CBD is more possible than we thought, since hempseed oil already can contain THC (as high as 50 ppm) it would logically also have even more CBD (hemp is defined by the UN as >1:1 CBD:THC ratio) which means that CBD could convert to THC and join the native THC thereby possibly causing a THC DUID or drug test interference.
  • will notorious drug warriors Sens. Feinstein and Grassley freak out and try to Schedule natural CBD.
  • it puts a dent in CBD-only lobbyists who diss THC in order to legalize CBD.
  • will CBD converting to THC run afoul of analog drug laws. (We can’t keep ignoring the elephant in the room, that “devil’s molecule” THC, so why not just push to legalize it all and unite instead of divide the entire Cannabis community?).

For CBD critics, now you got the Entourage Effect you say CBD products were lacking. (And why so many of us did in fact see dramatic results with just oral CBD.)

This issue also highlights the responsible answer when asked if CBD can cause a THC DUID or drug test positive: Yes, it may very well do so. If not from this then possibly from production or quality control issues. (But for the same reason, CBD will exert a bit of all the positive benefits of micro-doses of THC, CBN, and metabolites.)

Gaoni and Mechoulam reported that CBD was readily converted to ∆9-THC and iso-THC in a number of acidic reagents. They also reported that treatment of CBD with sulfuric acid in methanol gave a mixture of methoxy-iso-HHCs and methoxy-HHCs, and that the boiling of CBD with diluted HCl in ethanol gave two stereoisomers of 9-ethoxy-HHCs.” The THC metabolite used in urine tests is 11-Hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), could perhaps other cannabinoids or other acids could convert to it, thereby causing a drug test interference?

In Bonn-Miller et al: “[…]As THC-like intoxication effects may not only be driven by the conversion of CBD to THC but also the conversion of CBD to 9α-OH-HHC and 8α-OH-iso-HHC, it appears that oral administration of CBD could lead to unwanted consequences through a number of pathways. There is substantial promise in the development of CBD as a medicine. The current evidence indicates that gastric conversion of CBD to THC has been relatively consistently observed across multiple studies over the past half century; however, the circumstances in which this happens, and the subsequent clinical consequences, remain uncertain.”

TBH, in vivo looks way harder, but in vitro is totally possible. It opens up new products designed to take advantage of “Stony CBD.” I suspect we haven’t heard the end of this issue, and its ramifications could be far-reaching for the industry.

Learn more:

US Patent: Conversion of CBD to Δ8-THC and Δ9-THC

US Patent: Method for the production of dronabinol from cannabidiol, using a molecular sieve

Conversion of Cannabidiol Following Oral Administration: Authors’ Response to Grotenhermen et al” by Bonn-Miller, et al. Cannabis Cannabinoid Res. 2017; 2(1): 5–7.

Human Metabolites of Cannabidiol: A Review on Their Formation, Biological Activity, and Relevance in Therapy” by Ujváry and Hanuš. Cannabis Cannabinoid Res. 2016; 1(1): 90–101.

Identification of Psychoactive Degradants of Cannabidiol in Simulated Gastric and Physiological Fluid” by Merrick, et al. Cannabis and Cannabinoid Research (2016) 1:1, 102-112. 

Impact of enzymatic and alkaline hydrolysis on CBD concentration in urine” by Bergamaschi, et al. Anal Bioanal Chem. 2013 May; 405(14): 4679–4689.

Conversion of cannabidiol to ∆9-tetrahydrocannabinol and related cannabinoids in artificial gastric juice, and their pharmacological effects in mice” by Watanabe, et al. Forensic Toxicology (2007) 25:16–21, DOI 10.1007/s11419-007-0021-y.

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