Which cannabinoids produce a psychoactive effect?

Of all the cannabinoids, delta-9-THC has the strongest psychoactive effects: it is the main intoxicating compound in cannabis. Delta-8-THC and the semi-synthetic cannabinoids HHC, THC-P and THC-H also act on the same CB1 receptor in the brain and are intoxicating. CBD, CBG and CBC do not cause a high, human studies mostly found no cannabis-like effects from CBN, and THCV was indistinguishable from placebo in a small trial.

Which cannabinoids have psychoactive effects, and why?

The high from cannabis comes mainly from cannabinoids that activate the CB1 receptor, a receptor found mostly in the brain and nervous system (Crocq 2020). Delta-9-THC is the plant's main CB1 activator. In the living plant it occurs mostly as THCA, its acid form, which turns into THC when heated (Wang 2016); see What is THCA?

Strictly speaking, "psychoactive" means any substance that acts on the mind, while "intoxicating" means it causes a high. CBD can act in the brain, but it does not intoxicate. That is why many sources now call CBD non-intoxicating rather than non-psychoactive.

What does THC do in the brain?

THC binds to and activates CB1 receptors, the receptor that researchers cloned in 1990 (Matsuda 1990). These receptors sit on nerve cells and reduce how much signalling substance they release, which changes mood, memory and perception (Crocq 2020).

Typical short-term effects include euphoria and relaxation, an altered sense of time, impaired short-term memory and coordination, a faster heart rate and increased appetite. How strong they are depends on the dose, how THC is taken and the person. In a controlled trial, 10 mg of vaporised THC impaired verbal memory and caused short-lived psychotic symptoms in healthy volunteers (Englund 2023). Read more in What is THC?

Is CBD psychoactive?

CBD does not cause a high. The World Health Organization concluded in 2018 that "in humans, CBD exhibits no effects indicative of any abuse or dependence potential" (WHO 2018). In cell studies, CBD did not activate the CB1 receptor and instead reduced how strongly other compounds activated it (Laprairie 2015).

Does CBD weaken the effects of THC?

The results are mixed. In a 2013 study, healthy volunteers who took 600 mg of CBD before an injection of THC had less paranoia and less memory impairment than those who took placebo (Englund 2013). But in a 2023 randomised trial with 46 infrequent cannabis users, adding up to three times as much CBD as THC to vaporised cannabis did not change THC's effects on memory, psychotic symptoms or any other measure (Englund 2023). CBD therefore cannot be relied on to cancel out a high. For the differences in detail, see CBD vs THC.

Is CBN psychoactive?

CBN (cannabinol) forms when THC breaks down with age and exposure to air. A 2021 review found that most human studies did not show CBN producing cannabis-like effects, and that there was not enough evidence for the sleep claims made for it (Corroon 2021).

Since then, a small trial in 20 adults with insomnia disorder found that a single dose of 30 or 300 mg CBN did not significantly change time spent awake during the night, its main outcome. The higher dose changed some secondary measures, such as self-rated sleep quality, and the authors called for larger, longer trials (Lavender 2026). Read more in What is CBN? and CBD vs CBN.

Is THCV psychoactive?

THCV (tetrahydrocannabivarin) is related to THC but acts differently at the CB1 receptor. In a pilot trial, 10 male cannabis users took 10 mg THCV or placebo daily for five days. THCV was well tolerated and subjectively indistinguishable from placebo. When THC was given on day five, THCV made some of its effects weaker and others stronger. The authors warned that the study was very small (Englund 2016).

Claims that THCV boosts energy or focus have not been tested in controlled trials. Read more in What is THCV?

Are CBG and CBC psychoactive?

No. CBG (cannabigerol) and CBC (cannabichromene) are described as non-psychoactive cannabinoids (ElSohly 2017). They are mostly studied in the laboratory and in animals, and there is little research in people. See What is CBG? and What is CBC?

Are delta-8-THC, HHC, THC-P and THC-H psychoactive?

Yes. Delta-8-THC differs from delta-9-THC only in the position of one double bond. HHC (hexahydrocannabinol) is a hydrogenated form of THC. The large-scale production of HHC starts from hemp-derived CBD, which is converted into a mixture of delta-8- and delta-9-THC and then hydrogenated (Ujváry 2024). Preclinical studies indicate that HHC has THC-like effects, while its effects in people have hardly been studied. In a survey of 521 delta-8-THC users, most reported relaxation and difficulty concentrating, typical signs of a high (Kruger 2022). We explain HHC in more detail in What is HHC? Delta-10 THC is another THC isomer that is made from hemp-derived CBD in a lab.

THC-P (tetrahydrocannabiphorol) and THC-H (tetrahydrocannabihexol) were identified in a medicinal cannabis variety by Italian researchers in 2019 and 2020 (Citti 2019; Linciano 2020). They have longer side chains than THC: seven and six carbon atoms instead of five. In laboratory tests, THC-P bound to the CB1 receptor about 33 times more strongly than THC, and it produced THC-like effects in mice (Citti 2019). The plant contains only traces, so products sold as THC-P or THC-H are made semi-synthetically, and their effects and safety in people have hardly been studied.

Our article on synthetic and natural cannabinoids explains how the two groups differ.

Are psychoactive cannabinoids legal in the UK?

No, most are controlled. Cannabis is a Class B drug under the Misuse of Drugs Act 1971, and THC is controlled with it (Home Office 2024). According to the Advisory Council on the Misuse of Drugs (ACMD), many semi-synthetic cannabinoids, including THC homologues with longer or shorter side chains such as THC-P, are already Class B under the UK's generic definition of cannabinoids. HHC, HHCP and some related compounds were not captured by that definition. In August 2025 the government accepted the ACMD's advice to list them as named Class B drugs and said it would legislate when parliamentary time allows. In May 2026 it confirmed it would also control THCA, the acid form that turns into THC when heated. Until the new rules are in force, the ACMD notes that psychoactive examples fall under the Psychoactive Substances Act 2016 (ACMD 2025).

Pure CBD, as an isolated substance, is not controlled (Home Office 2024). Read more in is CBD legal in the UK?

Can hemp or CBD oil make you high?

Hemp grown for CBD is bred to contain very little THC, and a CBD oil itself does not cause a high. Full-spectrum oils contain natural traces of THC, and broad-spectrum oils are THC-free. We print the THC content of every batch on the label to two decimals. Traces of THC can still matter for drug tests; read Will CBD show up on a drug test? Our oils are cosmetic products for use on the skin.