Cannabidiol
Definition: Cannabidiol, or CBD, is the second most abundant cannabinoid in cannabis after THC. It doesn’t cause a high. CBD is the active ingredient in Epidiolex, an FDA-approved prescription drug for rare seizure disorders, and it’s sold widely in oils, gummies, and topicals, though evidence for most other uses is limited.
How Does CBD Work?
Unlike THC, CBD binds only weakly to CB1 and CB2 receptors, which is why it isn’t intoxicating. It acts on several other targets instead, including serotonin 5-HT1A receptors, TRPV1 receptors, and GPR55, and it slows the breakdown of the body’s own endocannabinoid anandamide. Scientists first isolated CBD in 1940, and Raphael Mechoulam’s team worked out its structure in 1963.
What Is CBD Proven to Help With?
The strongest evidence is for seizures. Large clinical trials led the FDA to approve Epidiolex for seizures linked to Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex. Research on anxiety, pain, sleep, and inflammation is promising in places but still mixed, small, or early. Many studies use doses far higher than what’s in a typical store-bought product.
Does CBD Have Side Effects?
Yes. Reported side effects include drowsiness, diarrhea, reduced appetite, and raised liver enzymes. CBD also interacts with medications broken down by the liver’s CYP450 enzymes, such as some blood thinners and seizure medications. Talk to a doctor or pharmacist before using CBD if you take prescription drugs.
Is CBD Legal?
Hemp-derived CBD became federally legal to produce under the 2018 Farm Bill, as long as the product came from hemp. The FDA still says it’s illegal to add CBD to food or market it as a dietary supplement, and in 2023 the agency asked Congress to create a new regulatory path. A federal law passed in 2025 also caps hemp products at 0.4 milligrams of total THC per container starting December 11, 2026, which will affect many full-spectrum CBD products.
Are CBD Products Accurately Labeled?
Often not. A 2017 study in JAMA tested 84 CBD products sold online and found only about 31% were accurately labeled for CBD content, and THC turned up in about 1 in 5. Look for products with a recent third-party certificate of analysis (COA) that matches the batch you’re buying.
Related terms: Epidiolex, Hemp, Entourage Effect, CBD Cartridge
Sources: FDA: Regulation of Cannabis and Cannabis-Derived Products, Including CBD; Bonn-Miller MO et al., “Labeling Accuracy of Cannabidiol Extracts Sold Online,” JAMA, 2017; DLA Piper: New federal restrictions on hemp (2025).
This entry is for general education and isn’t medical advice.
