THCP is usually introduced with a number: 33 times stronger than THC. The number comes from a real receptor-binding comparison, but not from a head-to-head experiment or a study in people. Its sibling, CBDP, gets less attention, even though the original cannabis sample contained considerably more CBDP than THCP. Here is what the research actually showed, what has been learned since, and what it means for the THCP products now sold in smoke shops, just weeks before federal law changes.
What are THCP and CBDP?
THCP (delta-9-tetrahydrocannabiphorol) and CBDP (cannabidiphorol) are close relatives of THC and CBD. Each has the same core structure as its familiar cousin, with one difference: a longer tail. THC and CBD carry a five-carbon side chain; THCP and CBDP carry a seven-carbon chain[1].
That tail matters. Cannabinoids come in families that differ only in side-chain length. The varins, such as THCV and CBDV, have three carbons; the standard compounds have five; the “phorols” have seven. Side-chain length is one of the main things that tunes how strongly a cannabinoid binds to the body’s cannabinoid receptors[1].
How were they discovered?
In 2019, Italian researchers analyzed an Italian medicinal cannabis variety called FM2 using ultra-high-performance liquid chromatography with high-resolution mass spectrometry, a technique that can pick out compounds present in tiny amounts by their exact mass[1]. They found two unfamiliar peaks, made both compounds in the lab, and confirmed that the synthetic versions matched the natural ones by their chromatography, mass spectra and other measurements[1]. That made them the first naturally occurring cannabinoids known to carry a seven-carbon side chain[1]. Our explainer on mass spectrometry in cannabis labs covers how this kind of detection works.
Both are rare. In the FM2 sample, the researchers estimated about 29 micrograms of THCP and 243 micrograms of CBDP per gram of plant material, compared with roughly 39 milligrams of THC and 56 milligrams of CBD[1]. That puts THCP at less than a thousandth of the THC content. A 2021 survey of cannabis flowers from several chemotypes found THCP at about 0.002% to 0.014% by weight in THC-dominant plants, with no clear relationship to THC levels, and did not detect it in CBD-dominant plants[2].
Is THCP really 33 times stronger than THC?
Roughly, in one kind of lab test. In people, nobody knows.
The “33 times” figure comes from a receptor-binding assay. The researchers measured how tightly THCP binds to human CB1 and CB2 receptors in a laboratory radioligand-binding assay, not in brain tissue or in a person. THCP had a CB1 affinity, expressed as Ki, of 1.2 nanomolar. The widely repeated 33-fold comparison comes from setting that result against a previously published THC value of 40 nanomolar; THC was not tested alongside THCP in the same experiment[1]. It is therefore an approximate comparison of receptor affinity, not a measurement showing that THCP produces 33 times the effect. Its affinity was close to that of CP55940, a potent synthetic cannabinoid[1]. It also bound CB2, at 6.2 nanomolar[1].
Binding tightly is not the same as being 33 times more intoxicating. How strongly a compound activates the receptor once bound, how much reaches the brain, and how quickly the body breaks it down all shape its effects, and none of these was measured in people.
The researchers then gave THCP to mice and ran the standard cannabinoid “tetrad”: movement, response to painful heat, catalepsy (freezing in place) and body temperature. THCP produced all four THC-like effects. Reduced movement appeared at 2.5 mg/kg; catalepsy and a reduced response to painful heat at 5 and 10 mg/kg; and lowered body temperature only at 10 mg/kg[1]. The authors concluded that THCP was as active as THC at lower doses, but that comparison relies on THC doses from earlier studies; the experiment did not include a THC group[1].
Why would a longer tail bind more tightly? Using computer models of the CB1 receptor, the team proposed that THCP’s seven-carbon chain fills the whole of a fatty channel inside the receptor, while THC’s shorter chain fills only part of it[1]. That is a modeled prediction, not a measured mechanism.
What about CBDP?
CBDP was found alongside THCP, and in the FM2 sample it was more abundant, but the original team did not test its biological activity, saying that testing it in the cannabinoid tetrad did not appear to be a high priority[1]. Later work has begun to fill the gap.
A 2024 study compared CBD and CBDP across several receptors in cell-based assays. The two looked broadly similar: both were weak at CB1 and CB2, with CB2 the more likely target, both weakly activated the serotonin 5-HT1A receptor, and CBD was slightly more potent than CBDP as a CB2 blocker. One difference stood out: at the mu-opioid receptor, CBDP enhanced the receptor’s response to a natural opioid peptide[3].
A 2026 study went further. Using mutated receptors, cell assays and molecular simulations, researchers found that CBDP acts as a negative allosteric modulator of CB1: rather than switching the receptor on, it binds at two separate sites and dampens how the receptor responds. In male mice given CBDP with THC, THC’s pain-relieving effect was preserved, with modest changes on a memory test; the authors called the results preliminary[4]. Unlike THCP, then, the longer chain does not appear to turn CBDP into a stronger intoxicant.
If THCP is so rare, where do THCP products come from?
At these trace concentrations, extracting useful quantities of THCP directly from cannabis would be impractical. Commercial THCP is therefore generally synthesized in a laboratory, although product labels do not always disclose the manufacturing route. Forensic chemists have identified THCP in products sold online and in smoke shops that are marketed as containing synthetically derived THCP[5]. Synthesis routes vary, and products are often blended with other cannabinoids, so a customer’s experience may not reflect THCP alone. Where lab-made products like these sit between approved medicines and street drugs is covered in our guide to synthetic cannabinoids.
That has two consequences. A product’s THCP content and purity depend entirely on the manufacturer, and any by-products of the synthesis may be in the product too. For what to look for, see our guide to reading a certificate of analysis. A standard potency panel reports a fixed list of cannabinoids, so a THCP claim is only meaningful if the lab actually measured THCP.
Is THCP safe?
There are no controlled studies of THCP in people, so its safety and dosing are unknown. One published human case report is cautionary. In a 2025 case report, an experienced cannabis user developed psychotic symptoms lasting about two days, including the belief that they were already dead, and attempted suicide after a single use of a gummy labeled as containing 8 mg of THCP[6]. The product was not independently analyzed, so its actual contents are unknown, and a single case cannot establish cause. It is a reminder that a receptor-binding number says nothing about what a safe dose is, and that a dose that sounds small may not be.
As of October 2025, a forensic lab that had identified THCP in ten seized products had not yet detected it in any toxicology case[5].
Is THCP legal?
Federal law is about to change. Under the new federal hemp definition, cannabinoids that the cannabis plant cannot produce naturally fall outside the definition of hemp on November 12, 2026. The rest of the changes take effect on December 11, 2026, including a total-THC standard, a cap of 0.4 milligrams of total THC per container, and the exclusion of cannabinoids that occur naturally but are manufactured outside the plant[7].
Because THCP occurs naturally, in trace amounts, commercial lab-made THCP falls in that second, December category, the same logic that applies to converted delta-8 THC. Our explainers on the 2026 hemp redefinition and on THC isomers and derivatives cover the details. The law also required the FDA to publish lists of naturally occurring cannabinoids and of cannabinoids with THC-like effects; as of late September 2026, it had not done so[7]. State laws vary, and this is not legal advice.
For a consumer-focused take on the “33 times” claim, see our sister site’s article on THCP.
The short version
THCP and CBDP are real, natural cannabinoids, first identified in 2019, that differ from THC and CBD only by a longer side chain. THCP binds CB1 much more tightly than THC in a receptor assay and produces THC-like effects in mice, but no one has measured its potency in people. One case report described severe psychosis and a suicide attempt after use of a gummy labeled as containing 8 mg of THCP, but the product was not independently analyzed. CBDP behaves much more like CBD, and may even dampen CB1 signaling. Because commercial THCP is generally synthesized rather than extracted, lab-made THCP products will fall outside the federal definition of hemp beginning December 11, 2026.
References
- 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.
- Bueno J, Greenbaum EA. (−)-trans-Δ9-Tetrahydrocannabiphorol content of Cannabis sativa inflorescence from various chemotypes. J Nat Prod. 2021;84(2):531-536.
- Haghdoost M, Young S, Holloway AK, et al. CBD versus CBDP: comparing in vitro receptor-binding activities. Int J Mol Sci. 2024;25(14):7724.
- Pandey P, Zagzoog AH, Zaharia T, et al. Cannabidiphorol (CBDP) acts as a negative allosteric modulator at two distinct sites of cannabinoid receptor 1. Commun Chem. 2026;9:186.
- Center for Forensic Science Research and Education. THCP (NPS Discovery monograph). October 2025.
- Greer D, Atherton J, Girgis J. Psychosis and suicide attempt following a single use of delta-9-tetrahydrocannabiphorol: a case report. PCN Reports. 2025.
- Neuhofer ZT. Changes to the statutory definition of hemp and implications for agricultural policy. Congressional Research Service In Focus IF13136. Updated 28 September 2026.
This article is an educational summary of published research. It is not medical or legal advice. Laws on hemp-derived cannabinoids vary by state and are changing.
Editor’s note: Originally published April 2022 by Derek Johnson; rewritten and expanded November 2026 with the details of the 2019 discovery, newer CBDP research, safety reports and the 2026 federal hemp changes.
Last updated: November 2026.
