October 18, 2025: What is THCP?

October 18, 2025

THCP or tetrahydrocannabiphorol is a phytocannabinoid recently discovered by Citti et al in 2019. It was isolated from the Cannabis Sativa plant and (-)-trans-Δ9-THCP was shown to have 33 times more binding affinity at the CB1 receptor in vitro compared to (-)-trans-Δ9-THC1. The psychopharmacologic activity of delta-9 THC is thought to occur through activation of CB1 receptors (CB1 is concentrated in the CNS). CB2 receptors appear to be involved in immune system modulation2. The structural difference between THC and THCP is the alkyl side chain where THCP has a seven-carbon chain and the THC has a five-carbon chain. The senior author of Citti et al gave an interview regarding the discovery of THCP and said “We can only speculate that they are more lipophilic molecules than the respective CBD and THC and therefore they could cross the blood-brain barrier more easily by passive diffusion. However, the road is still long for a clear understanding of their biological activity.”3 THCP is currently legal federally but on January 1, 2026 will become illegal in any amount in the state of Tennessee4.

Clinically, we have noticed both more severe and prolonged periods of intoxication from THCP. We have seen poisoning in pediatrics to require intubation and mechanical ventilation for respiratory depression. Multiple day hospital stays have been necessary for both adult and pediatric patients. Treatment is supportive care. It is important to be prepared when encountering THCP intoxication that the clinical course could be longer and require more support than delta-9 THC.

Rebecca Bruccoleri, MD, Medical Director, Tennessee Poison Center

Reference:

  1. Citti C, Linciano P, Russo F, Luongo L, Iannotta M, Maione S, Laganà A, Capriotti AL, Forni F, Vandelli MA, Gigli G, Cannazza G. A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ9-tetrahydrocannabinol: Δ9-Tetrahydrocannabiphorol. Sci Rep. 2019 Dec 30;9(1):20335. doi: 10.1038/s41598-019-56785-1. PMID: 31889124; PMCID: PMC6937300.
  2. Howlett AC, Abood ME. CB1 and CB2 Receptor Pharmacology. Adv Pharmacol. 2017;80:169-206. doi: 10.1016/bs.apha.2017.03.007. Epub 2017 Jun 12. PMID: 28826534; PMCID: PMC5812699.
  3. J. Crossney, Cannabis Science and Technology 3(1), 26-27 (2020)
  4. Barker, Jessica. New guidance on hemp-derived cannabinoid products: What will change on January 1, 2026. WKRN News 2. Website: New guidance on hemp-derived cannabinoid products in TN: What will change on Jan. 1, 2026. Accessed October 18, 2025.

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