Cannabinoids are a family of more than 140 lipophilic molecules that bind, directly or indirectly, to CB1 and CB2 receptors of the endocannabinoid system. Each compound's effects depend on its binding affinity, its metabolic half-life, and whether it acts as a full agonist, partial agonist, or antagonist. Delta-9-tetrahydrocannabinol (THC) produces the primary psychoactive and analgesic effects; cannabidiol (CBD) modulates without intoxicating; and minor cannabinoids such as CBG, CBN, and THCV occupy distinct receptor profiles with far weaker clinical evidence. Below is a mechanism-level list of the major and minor cannabinoids, their quantified receptor activity, and the edge cases most explainers omit.
The receptor mechanism that sorts every cannabinoid
Every cannabinoid's effect profile follows from three variables: binding affinity at CB1 and CB2, intrinsic efficacy, and degradation route. CB1 is concentrated in the central nervous system at roughly 10 times the density of CB2 in brain tissue. CB2 clusters on immune cells and peripheral tissue. THC has an equilibrium dissociation constant (Ki) of about 10–40 nanomolar at CB1 and acts as a partial agonist with roughly 20–30 percent the intrinsic efficacy of the endogenous ligand anandamide.
CBD is the counterintuitive case. Its CB1 affinity is weak (Ki roughly 1,000–4,000 nanomolar), and it functions as a negative allosteric modulator, meaning it binds a separate site and lowers THC's receptor signaling rather than blocking the receptor directly. In plain terms: CBD does not compete with THC at the receptor; it changes the receptor's shape. That distinction explains why 1:1 THC:CBD products feel less intense than THC alone at the same THC dose.
The endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG) are degraded within seconds to minutes by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). Plant cannabinoids are not degraded by these enzymes, which is why their effects last 2–8 hours while endogenous signaling is transient.
Quantified potency comparison of the major cannabinoids
The table below reconciles the numbers used throughout this article. Affinity values are order-of-magnitude Ki figures from receptor-binding literature; half-lives are plasma elimination estimates. Higher Ki means weaker binding.
| Cannabinoid | Primary target | Approx. CB1 Ki (nM) | Intrinsic action | Plasma half-life |
|---|---|---|---|---|
| THC | CB1, CB2 | 10–40 | Partial agonist | 1.5–4 hours |
| CBD | CB1 (allosteric), 5-HT1A, TRPV1 | 1,000–4,000 | Negative allosteric modulator | 18–32 hours |
| CBG | CB1, CB2 | 100–800 | Partial agonist | 1–3 hours |
| CBN | CB1 (weak), CB2 | 300–2,000 | Weak partial agonist | 1–2 hours |
| THCV | CB1 (antagonist), CB2 | 60–150 | Antagonist at low dose | 2–4 hours |
| CBDV | TRPV1, CB1 (weak) | >2,000 | Weak modulator | 4–8 hours |
| CBC | CB2, TRPA1 | >2,000 | Indirect modulator | 2–3 hours |
The key inconsistency to reconcile: CBN is often marketed as strongly sedative, but its CB1 affinity (300–2,000 nM) is roughly 10 to 50 times weaker than THC's. Any sedation from CBN is likely additive to residual THC or terpene effects, not a potent receptor mechanism of its own.
The major cannabinoids: THC and CBD
THC's analgesic and intoxicating effects peak in plasma 10–30 minutes after inhalation and 1–2 hours after oral ingestion. Oral bioavailability is low, roughly 6–10 percent, because of first-pass liver metabolism into 11-hydroxy-THC, a metabolite 2–3 times more potent than the parent compound. That metabolite explains why the same milligram dose hits harder orally than inhaled.
CBD's half-life is 5 to 10 times longer than THC's, which means steady-state accumulation over 3–5 days of twice-daily dosing. A 25 mg oral dose can reach plasma concentrations near 1–2 nanograms per milliliter, but inter-individual variability exceeds 10-fold because of CYP2C19 and CYP3A4 enzyme differences. Drug interaction is the practical hazard: CBD inhibits CYP3A4 and can raise blood levels of tacrolimus, clobazam, and some anticoagulants.
A professional caveat: the FDA has approved only one CBD product, Epidiolex, for seizures associated with Lennox-Gastaut and Dravet syndromes, per FDA approval in 2018. No over-the-counter CBD product has approved efficacy claims.
Minor and trace cannabinoids with real receptor activity
CBG is the biosynthetic precursor; all other cannabinoids derive from cannabigerolic acid, and most cannabis flowers contain under 1 percent CBG by dry weight. Its partial CB1 agonism is weak but measurable, and its affinity for the alpha-2 adrenergic receptor is the proposed mechanism behind reported eye-pressure and muscle-tension effects. Evidence remains preliminary.
THCV is the standout for a counterintuitive mechanism: at low doses (under roughly 3 mg) it acts as a CB1 antagonist, which may blunt appetite and intoxication; at higher doses it can behave as an agonist. This dose-dependent reversal is why THCV research results are difficult to compare across studies.
CBN is the oxidation product of THC, forming as cannabis ages or is exposed to light and heat. A common misconception is that old cannabis converts THC to CBN at high yield; in practice, storage at room temperature converts only 5–10 percent of THC to CBN over a year. CBDV and CBC have weak, indirect activity and the thinnest clinical evidence of the group.
The time course of cannabinoid onset and clearance
The timeline below shows the practical window for the major routes and compounds. These are typical ranges, not guarantees; body fat percentage and frequency of use shift every row.
| Time point | Inhaled THC | Oral THC | Oral CBD | Detection window (urine) |
|---|---|---|---|---|
| Onset | 2–10 minutes | 30–90 minutes | 30–90 minutes | — |
| Peak plasma | 10–30 minutes | 1–2 hours | 1–3 hours | — |
| Subjective offset | 2–4 hours | 4–8 hours | 4–8 hours | — |
| Half-life | 1.5–4 hours | 2–4 hours | 18–32 hours | — |
| Urine clearance | 3–30 days | 3–30 days | 2–5 days | Chronic users up to 30 days |
Fat solubility is the reason detection outlasts intoxication so dramatically. THC and its metabolites store in adipose tissue with an apparent terminal half-life of 20–30 hours, releasing slowly for days to weeks; chronic heavy users can test positive for up to 30 days after last use.
What the evidence does not support, and where the risks sit
The largest gap is clinical: most minor cannabinoid claims rest on cell-culture or animal data with no human dosing trials. A 2022 review of CBG, CBN, and THCV found fewer than 20 controlled human studies across all three combined. Treat marketed effects as hypotheses, not established science.
Misconceptions worth correcting directly. CBD is not "non-psychoactive"; it is non-intoxicating, and it still modulates serotonin and TRPV1 signaling. Full-spectrum products contain trace THC (up to 0.3 percent by dry weight under US federal law, per the 2018 Farm Bill) that can accumulate with repeated high doses. "Indica versus sativa" does not reliably predict cannabinoid ratio; chemotype analysis does.
Red-flag warnings, always worth stating plainly:
- Do not combine high-dose CBD with blood thinners, transplant drugs, or epilepsy medication without a prescriber's review; CYP interactions are real.
- Avoid all cannabinoid products in pregnancy and under age 21; the CDC documents developmental and psychiatric risk.
- High-potency THC concentrates (over 60 percent THC) carry higher risk of cannabis hyperemesis syndrome and psychosis in predisposed users.
- Driving within 4 hours of inhaled THC impairs reaction time even when the user feels sober.
The number that should reconcile every threshold in this article: 0.3 percent THC is the federal legal limit for hemp, while concentrates can exceed 60 percent, a 200-fold spread that makes "cannabis dose" meaningless without a product-specific label.
What to actually do with this list
Match the compound to the receptor profile, not the marketing name. If the goal is intoxication or acute pain, THC is the active molecule; start at 2.5 mg oral or one 2–3 second inhalation and wait 90 minutes before redosing. If the goal is non-intoxicating modulation, select a CBD-dominant product and expect 3–5 days to reach steady state. For minor cannabinoids, buy third-party lab-tested products showing cannabinoid percentages, since label accuracy varies widely and several analyses find actual content 10–50 percent off the stated amount.
Track your own response against the mechanism table: note dose in milligrams, route, and onset time, and compare across 3–4 sessions before drawing conclusions. Because inter-individual variability exceeds 10-fold for oral CBD and roughly 3-fold for inhaled THC, published averages describe populations, not you. The limits remain firm: minor cannabinoid evidence is early-stage, product regulation is inconsistent, and any interaction with prescription drugs deserves a clinician's review before the first dose.