Δ8-Tetrahydrocannabinol (delta-8-THC,[a]Δ8-THC) is apsychoactivecannabinoid found in theCannabis plant.[1] It is anisomer ofΔ9-tetrahydrocannabinol (delta-9-THC, Δ9-THC), with which it co-occurs inhemp; natural quantities of ∆8-THC found in hemp are low. Psychoactive effects are similar to that of Δ9-THC, withcentral effects occurring by binding tocannabinoid receptors found in various regions of the brain.[2]
∆8-THC is moderately lesspotent than Δ9-THC.[5][6] This means that while its effects are similar to that of Δ9-THC, as both are psychoactive cannabinoids, it would take more ∆8-THC to achieve a comparable level of effect.
A 1973 study testing the effects of ∆8-THC in dogs and monkeys reported that a single oral dose of 9,000 milligrams per kilogram of body mass (mg/kg) was nonlethal in all dogs and monkeys studied.[7] The same study reported that themedian lethal dose of ∆8-THC in rats was comparable to that of ∆9-THC.[7] Both isomers of THC have been found to cause a transient increase in blood pressure in rats,[8] although the effects of cannabinoids on thecardiovascular system are complex.[9] Animal studies indicate that ∆8-THC exerts many of itscentral effects by binding tocannabinoid receptors found in various regions of the brain, including thecerebral cortex,thalamus,basal ganglia,hippocampus, andcerebellum.[10][11]
As of 2022, there had been at least 104adverse event reports made for ∆8-THC,[12] and at least two deaths associated with ∆8-THC products.[13] US nationalpoison control centers received 2,362 exposure cases of Δ8-THC products between 1 January 2021 and 28 February 2022; 58% of these exposures involved adults, and 70% thought they required medical care.[12]
As of 2022, the safety profile, including risks ofpsychosis and addiction after regular, long-term ∆8-THC use was unknown.[14]
Thepharmacokinetic profile of ∆8-THC is also similar to that of ∆9-THC.[5][6] Following ingestion in humans,hepaticcytochrome P450 enzymes includingCYP2C9 andCYP3A4 first convert ∆8-THC into 11-hydroxy-Δ8-tetrahydrocannabinol (11-OH-Δ8-THC).[18][19] Next,dehydrogenase enzymes convert 11-OH-Δ8-THC into 11-nor-Δ8-tetrahydrocannabinol-9-carboxylic acid (11-nor-Δ8-THC-9-COOH, also known as Δ8-THC-11-oic acid).[19][20] Finally, Δ8-THC-11-oic acid undergoesglucuronidation byglucuronidase enzymes to form 11-nor-Δ8-tetrahydrocannabinol-9-carboxylic acid glucuronide (Δ8-THC-COOH-glu),[19][20] which is then excreted in the urine.[21][22]
∆8-THC is a tricyclicterpenoid. Although it has the same chemical formula as ∆9-THC, one of its carbon-carbondouble bonds is located in a different position.[5] In ∆8-THC, the double bond is between the eighth and ninth carbons in structure, while in Δ9-THC, the double bond is between the ninth and tenth carbons in structure.
∆8-THC has a double bond (a) between the carbon atoms labeled 8 and 9.∆9-THC has a double bond (a) between the carbon atoms labeled 9 and 10.
This difference in structure increases the chemical stability of ∆8-THC relative to ∆9-THC, lengthening shelf life and allowing the compound to resist undergoingoxidation tocannabinol over time.[15] Like other cannabinoids, ∆8-THC is verylipophilic (logP = 7.4[23]). It is an extremely viscous, colorless oil at room temperature.[24]
"The psychoactive (and probably the toxic) effects of synthetic cannabinoid receptor agonists are likely due to their action as full receptor agonists and their greater potency at CB1 receptors."
However, ∆8-THC and ∆9-THC arepartial agonists of cannabinoid receptors.[16] They are less potent than many synthetic cannabinoids.[30] It has not been definitively proven if full agonism is the reason for the greater incidence of adverse reactions to synthetic cannabinoids since ∆9-THC has been shown to act as a full CB1 receptor agonist on specific CB1 receptors located in the hippocampus section of the brain.[31] Furthermore, the synthetic cannabinoidEG-018 acts as a partial agonist.[32] The classical cannabinoid structure is that of a dibenzopyran structure. This group includes THC. THC interacts with a different spot inside the CB1 receptor than synthetic cannabinoids such as JWH-018. This may explain the differences in adverse reactions to synthetic cannabinoids.[33]
∆8-THC is typically synthesized fromcannabidiol extracted fromhemp,[34] as the natural quantities of ∆8-THC found in hemp are low. This is calledsemisynthesis or partial synthesis. The reaction often yields a mixture that contains other cannabinoids and unknown reaction by-products. As a result, most products sold as ∆8-THC are not actually pure ∆8-THC.[34] Little is known about the identity and the health effects of the impurities.[34] Some manufacturers of ∆8-THC may usehousehold chemicals in the synthesis process, potentially introducing harmfulcontaminants.[12] In that sense, ∆8-THC is often encountered as a semi-synthetic phytocannabinoid, obtained by (partial) chemical synthesis. It is not to be confused with the termsynthetic cannabinoid, however.
Thepartial synthesis of ∆8-THC was published in 1941 byRoger Adams and colleagues at theUniversity of Illinois.[35] In 1942, the same research group studied its physiological and psychoactive effects after oral dosing in human volunteers.[36]Total syntheses of ∆8-THC were achieved in 1965 byRaphael Mechoulam.[37] In 1966, the chemical structure of ∆8-THC isolated from cannabis was characterized using modern methods by Richard L. Hively, William A. Mosher, and Friedrich W. Hoffmann at theUniversity of Delaware.[38] Astereospecific synthesis of ∆8-THC fromolivetol andverbenol was reported byRaphael Mechoulam and colleagues at theWeizmann Institute of Science in 1967.[39] ∆8-THC was often referred to as "Delta-6-THC" (Δ6-THC) in early scientific literature, but this name is no longer conventional among most authors.[40]
In 1937, cannabis was effectively outlawed by theMarihuana Tax Act, which imposed a prohibitory excise tax. In 1970, the Marihuana Tax Act was repealed and superseded by theControlled Substances Act (CSA).[43] The CSA replaced "[a] patchwork of regulatory, revenue, and criminal measures"[44] relating to drug control with a "comprehensive regulatory regime".[45]
As of 2024, 24 states havelegalized recreational cannabis, with others having reduced penalties.[46] Section 10113 of theAgriculture Improvement Act of 2018 (2018 Farm Bill), amended the Agricultural Marketing Act of 1946, and added a new subtitle G related to hemp.[47] Under section 297A of that subtitle, is the definition of hemp as used in federal law:
The term "hemp" means the plant Cannabis sativa L. and any part of that plant, including the seeds thereof and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.
— Section 297A of the Agricultural Marketing Act of 1946 (7 U.S.C. 1639o)
In October 2020, theDEA Interim Final Rule[48] addressedsynthetic cannabinoids. Some believed that this also applied to ∆8-THC products and other hemp derivatives addressed by the Farm Bill.[49] TheUniversity of ArkansasNational Agriculture Law Center has maintained an index of litigation surrounding hemp and ∆8-THC products.[50] Despite claims of legality by manufacturers, independent testing of products has often uncovered that many products contain ∆9-THC concentrations beyond the allowable 0.3 percent legal threshold .[51][52] There exists a "hazy legal landscape" surrounding ∆8-THC and other hemp-derived tetrahydrocannabinols.[53]
On 12 November 2025, in order to end the2025 United States federal government shutdown, theUnited States Congress passed the Continuing Appropriations, Agriculture, Legislative Branch, Military Construction and Veterans Affairs, and Extensions Act, 2026, which contains arider under section 781 that, effective 12 November 2026, will redefine the federal legal definition of hemp in a way that would "likely make industrial hemp-derived cannabis products, including delta-8 and delta-10 THC as well as synthetic THC products like edibles, drinks, oils and vapes, incredibly difficult, if not impossible, to sell legally".[54]
∆8-THC has not been evaluated or approved by the USFood and Drug Administration (FDA) for safe use in any context.[12] The FDA has taken action against businesses that have illegally marketed ∆8-THC for therapeutic use.[12] The FDA has also taken action against businesses that sold ∆8-THC in forms that closely resemble (typically non-psychoactive) food products such as chips or cookies.[12]
While legal action against ∆8-THC has not been widespread in the United States, some people have faced legal repercussions, leading to confusion as to its legal status within the United States.[55][56][57][58]
In 2021, one store owner inMenomonee Falls, Wisconsin was facing a sentence of up to 50 years for allegedly selling ∆8-THC products with illegal amounts of ∆9-THC.[59] Other raids and arrests have happened due to the ∆9-THC content of these products inNorth Carolina andTexas, among other places.[60][61][62] In 2022,Catoosa County, Georgia Sheriff Sisk announced to prosecute stores distributing ∆8-THC with non-compliant ∆9-THC levels: "The products the sheriffs office has purchased and tested all contain significant levels of delta-9. [We have the] evidence needed to move forward with prosecution and seizures."[63] There are also issues related to incidental manufacture of ∆9-THC, as it is produced as an intermediate in the acid catalyzed isomerization ofCBD.[2]
The first case before aUnited States courts of appeals relating to the legality of ∆8-THC wasAK Futures v. Boyd St. Distro (2022), a trademark lawsuit where the9th Circuit found that ∆8-THC products qualified for trademark protection. The legality of ∆8-THC was addressed brieflyin dicta, where the court held the products subject of the litigation were lawful.[65] Conversely, the4th Circuit upheld ∆8-THC regulations in Virginia, finding the Farm Bill did not preempt state law.[66]
In March 2024, a study of self-reportedprevalence of Δ8-THC use among UStwelfth graders was published: Of those reporting Δ8-THC use, 35% had used it at least 10 times in the past 12 months. Consumption was lower in Western than Southern and in states, where Δ8-THC was regulated versus not regulated.[4]
Although it is a minor constituent ofCannabis, no large clinical studies have been conducted on ∆8-THC alone as of 2022.[75] One study (ongoing as of November 2023) is focused on determining the degree of pharmacologic and pharmacokinetic similarity between ∆8-THC and ∆9-THC.[76]
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^abThompson GR, Rosenkrantz H, Schaeppi UH, Braude MC (July 1973). "Comparison of acute oral toxicity of cannabinoids in rats, dogs and monkeys".Toxicology and Applied Pharmacology.25 (3):363–372.doi:10.1016/0041-008x(73)90310-4.PMID4199474.
^Charalambous A, Marciniak G, Shiue CY, Dewey SL, Schlyer DJ, Wolf AP, et al. (November 1991). "PET studies in the primate brain and biodistribution in mice using (-)-5'-18F-delta 8-THC".Pharmacology, Biochemistry, and Behavior.40 (3):503–507.doi:10.1016/0091-3057(91)90354-5.PMID1666914.S2CID140208679.
^Tripathi HL, Vocci FJ, Brase DA, Dewey WL (1987). "Effects of cannabinoids on levels of acetylcholine and choline and on turnover rate of acetylcholine in various regions of the mouse brain".Alcohol and Drug Research.7 (5–6):525–532.PMID3620017.INIST7401152.
^abAbrahamov A, Abrahamov A, Mechoulam R (May 1995). "An efficient new cannabinoid antiemetic in pediatric oncology".Life Sciences.56 (23–24):2097–2102.doi:10.1016/0024-3205(95)00194-b.PMID7776837.
^abcVillamor JL, Bermejo AM, Tabernero MJ, Fernandez P, Sanchez I (December 1998). "GC/MS Determination of 11-Nor-9-Carboxy-Δ 8 -tetrahydrocannabinol in Urine from Cannabis Users".Analytical Letters.31 (15):2635–2643.doi:10.1080/00032719808005332.
^abValiveti S, Hammell DC, Earles DC, Stinchcomb AL (June 2005). "LC-MS method for the estimation of delta8-THC and 11-nor-delta8-THC-9-COOH in plasma".Journal of Pharmaceutical and Biomedical Analysis.38 (1):112–118.doi:10.1016/j.jpba.2004.11.055.PMID15907628.
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^Huffman JW, Padgett LW (31 May 2005). "Recent developments in the medicinal chemistry of cannabimimetic indoles, pyrroles and indenes".Current Medicinal Chemistry.12 (12):1395–1411.doi:10.2174/0929867054020864.PMID15974991.
^Adams R, Cain CK, McPhee WD, Wearn RB (August 1941). "Structure of Cannabidiol. XII. Isomerization to Tetrahydrocannabinols 1".Journal of the American Chemical Society.63 (8):2209–2213.doi:10.1021/ja01853a052.
^Hively RL, Mosher WA, Hoffmann FW (April 1966). "Isolation of trans-delta-tetrahydrocannabinol from marijuana".Journal of the American Chemical Society.88 (8):1832–1833.doi:10.1021/ja00960a056.PMID5942992.
^Mechoulam R, Braun P, Gaoni Y (August 1967). "A stereospecific synthesis of (-)-delta 1- and (-)-delta 1(6)-tetrahydrocannabinols".Journal of the American Chemical Society.89 (17):4552–4554.doi:10.1021/ja00993a072.PMID6046550.
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^Tadlock C (7 April 2023)."Cannabis sales have buyers, sellers on a different high".thecharlottepost.com. The Charlotte Post. Retrieved7 April 2023.Located at vape shops, convenience stores and even gas stations, Delta-8 is well-accessible to consumers. Products are available in different forms, including gummies, chocolate, vaping cartridges, infused drinks and even breakfast cereal.
