What Is CBD? A Plain-English Guide to Cannabidiol

CBD (cannabidiol) is a natural compound from the cannabis plant that does not cause a “high.” It is one of more than 100 cannabinoids found in cannabis, and most CBD sold in the US is made from hemp. The only FDA-approved CBD medicine is Epidiolex, a prescription drug for certain rare seizure disorders; the over-the-counter oils, gummies and creams you see in stores are not FDA-approved, and evidence for most popular uses is still limited.

What exactly is CBD?

CBD is short for cannabidiol. It belongs to a family of plant compounds called cannabinoids. The National Center for Complementary and Integrative Health (NCCIH) describes CBD and THC as the two main cannabinoids in cannabis, out of more than 100 that have been identified.

CBD is extracted from the plant and usually mixed into an oil or other base. Because it dissolves in fat rather than water, it is most commonly sold as an oil or alcohol-based liquid, according to a 2020 review of CBD delivery in Pharmaceuticals. To learn how that extraction happens, see how CBD oil is made.

Hemp vs marijuana: where does CBD come from?

Hemp and marijuana are both Cannabis sativa. The difference is how much THC the plant contains. NCCIH explains that plants with very little THC are classed as “industrial hemp” under US law, while “marijuana” refers to cannabis with substantial THC.

According to the FDA, the 2018 Farm Bill defined hemp as cannabis with no more than 0.3% delta-9 THC on a dry weight basis and removed it from the federal list of controlled substances. Even so, the FDA still regulates hemp-derived CBD products under food and drug law. Hemp and CBD laws vary by state and are changing, so check your state’s current rules before you buy or travel.

How is CBD different from THC?

THC (tetrahydrocannabinol) is the compound behind the marijuana “high.” NCCIH states that THC is primarily responsible for marijuana’s effects on a person’s mental state. CBD works differently: the Epidiolex prescribing label notes that CBD does not appear to act through the body’s cannabinoid receptors, and it is not a controlled substance.

In 2018 the World Health Organization’s drug dependence committee reviewed pure CBD and recommended that it not be placed under international drug control, saying it “presents no potential for abuse or dependence.” Some CBD products do contain THC, though, which can matter for effects and drug tests. Read more in does CBD get you high?

What forms does CBD come in?

CBD is sold in many formats. Each one changes how fast it is absorbed and how easy it is to measure.

• Oils and tinctures: liquid drops, often placed under the tongue.
• Gummies and edibles: swallowed and digested, so effects are slower. Taking CBD with a high-fat meal increased absorption about fourfold in studies summarized in the 2020 Pharmaceuticals review.
• Topicals: creams and balms applied to the skin.
• Vapes: inhaled liquids. In a 2017 JAMA study, vape liquids were the most often mislabeled product type: only 3 of 24 were accurately labeled.

Full spectrum, broad spectrum and isolate: what do they mean?

These labels describe what else is in the extract besides CBD. There is no official federal definition, but a 2024 study in Frontiers in Pharmacology used these working definitions:

• Full spectrum: a hemp extract left largely as-is, containing CBD, small amounts of THC and other cannabinoids.
• Broad spectrum: an extract with THC removed to non-detectable levels, but other cannabinoids kept.
• Isolate: more than 95% pure CBD. Learn more in what is CBD isolate?

Many brands claim full-spectrum products work better because of an “entourage effect.” A 2023 scoping review in Biomedicines concluded there is “a lack of sound evidence” for that claim. In the 2024 study, 26% of products did not match the type claimed on the package.

What does research actually support?

The strongest evidence is for specific seizure disorders. The FDA has approved Epidiolex, a purified CBD oral solution, for seizures associated with Lennox-Gastaut syndrome, Dravet syndrome or tuberous sclerosis complex. The current label covers patients 1 year of age and older. It is a prescription drug used under medical supervision, not the same as a store-bought oil.

For other uses, the picture is much weaker. NCCIH reports:

• Other forms of epilepsy: not enough research.
• Anxiety: limited evidence, including one small study of 24 people during a simulated public speaking test.
• Sleep, PTSD and other conditions: evidence is uncertain or limited.
• Glaucoma: an animal study found CBD applied to the eye may increase eye pressure, the opposite of what is wanted.

Read our editorial policy for how we rate evidence.

Is CBD safe?

CBD is not risk-free. The FDA says CBD “can cause liver injury” and “can affect how other drugs you are taking work, potentially causing serious side effects.” It also lists drowsiness, diarrhea, decreased appetite, and mood changes such as irritability. Combining CBD with alcohol or sedating drugs increases the risk of drowsiness and injury.

The FDA notes that male reproductive toxicity has been reported in animal studies, and that the effects of long-term daily use are not well understood. Effects on a developing fetus or breastfed baby are unknown; see is CBD safe during pregnancy?

How do you read a CBD lab report (COA)?

A certificate of analysis (COA) is a lab report showing what a product contains. Labels alone are not reliable. In the 2017 JAMA study of 84 products bought online, only about 31% were accurately labeled for CBD, and THC was found in 18 of them. In the 2024 study of 202 products, 74% were off by more than 10% from the CBD claimed.

1. Match the batch. Check that the batch or lot number on the COA matches the one on your package.
2. Check who tested it. Look for an independent lab, not the brand itself, and a recent test date.
3. Compare CBD content. Researchers usually treat 90%–110% of the labeled amount as accurate.
4. Look at THC. Make sure THC is listed and fits the product type claimed (for example, “THC-free”).
5. Review contaminant tests. Look for heavy metals, pesticides and residual solvents. The 2024 study found lead in 42 of 202 products.

Frequently asked questions

Sources

• FDA — FDA Regulation of Cannabis and Cannabis-Derived Products, Including CBD
• FDA — What You Need to Know About Products Containing Cannabis or Cannabis-Derived Compounds, Including CBD
• FDA — FDA and Cannabis: Research and Drug Approval Process
• DailyMed (NLM) — Epidiolex (cannabidiol) prescribing information
• NCCIH — Cannabis (Marijuana) and Cannabinoids: What You Need To Know
• World Health Organization — News Briefing, 40th Expert Committee on Drug Dependence
• JAMA (via PMC) — Bonn-Miller et al., Labeling Accuracy of Cannabidiol Extracts Sold Online (2017)
• Frontiers in Pharmacology (via PMC) — Gidal et al., Product Labeling Accuracy and Contamination Analysis of Commercially Available CBD Products (2024)
• Pharmaceuticals (via PMC) — Millar et al., Towards Better Delivery of Cannabidiol (2020)
• Biomedicines (via PMC) — Christensen et al., Decoding the Postulated Entourage Effect of Medicinal Cannabis (2023)