CBD is found in the flowers and leaves of the cannabis plant, sold in retail shops and online across most of the United States, and legal at the federal level when derived from hemp containing less than 0.3% THC. Depending on what brought you here, “where is CBD” might mean where it comes from botanically, where it ends up in your body, or where you can legally buy it. This guide covers all three.
Where CBD Comes From in the Plant
CBD is one of over a hundred compounds produced by the cannabis sativa plant. The highest concentrations sit in the flower, specifically in tiny, mushroom-shaped glands called trichomes that coat the surface of the bud. These glands secrete a sticky resin packed with cannabinoids and aromatic compounds called terpenes. The small leaves surrounding the flower, known as bracts, carry the densest covering of trichomes on the entire plant, making them the primary source of both CBD and THC.
Trichomes also appear on stems and larger leaves, but in much lower numbers. That’s why commercial CBD extraction focuses almost entirely on the flowering tops of the plant rather than stalks or seeds.
Hemp vs. Marijuana: The Legal Line
Both hemp and marijuana are cannabis sativa, but U.S. law draws a hard line between them. Hemp is defined as any cannabis plant containing no more than 0.3% THC by dry weight. Marijuana is everything above that threshold and remains federally illegal.
The 2018 Farm Bill removed hemp from the Controlled Substances Act, which effectively legalized hemp-derived CBD nationwide. The U.S. Domestic Hemp Production Program now provides federal oversight of hemp farming, though individual states can set their own rules or even ban hemp production entirely. If a CBD product comes from hemp and stays under the 0.3% THC ceiling, it is legal under federal law.
Where CBD Goes in Your Body
Once CBD enters your bloodstream, it interacts with your body’s endocannabinoid system, a network of receptors involved in regulating pain, mood, inflammation, and sleep. Unlike THC, CBD does not bind strongly to the two main cannabinoid receptors (CB1 and CB2). Instead, it acts as an indirect modulator, influencing how those receptors respond to other signals. It also appears to interact with pain-sensing receptors involved in how your nervous system processes temperature and inflammation.
Because CBD does not activate the same receptor that THC does in the brain, it doesn’t produce a high. Its effects are subtler and harder to pinpoint, which is part of why research into its exact mechanisms is still evolving.
How Delivery Method Affects Absorption
Where CBD enters your body matters a lot for how much of it actually reaches your bloodstream. Oral CBD, the kind you swallow in a capsule or gummy, has a bioavailability estimated at roughly 6%. That means your liver and digestive tract break down the vast majority of it before it ever circulates. Eating CBD with fatty foods can improve absorption somewhat, since the compound dissolves in fat rather than water.
Sublingual products (oils held under the tongue) are marketed as a faster route, but research suggests much of the dose still ends up swallowed and processed through the gut. CBD’s fat-loving chemistry causes it to accumulate in the lining of the mouth rather than passing quickly into blood vessels.
Inhaled CBD tells a different story. Smoking or vaping delivers roughly 31% of the dose into the bloodstream, with peak levels appearing within about three minutes. That’s a dramatically faster and more efficient route, though it comes with the respiratory tradeoffs of inhaling heated material. Newer technologies like nano-emulsion formulations and intranasal sprays are attempting to close that gap for people who prefer non-inhaled options, with some showing absorption rates several times higher than standard CBD oils.
Where You Can Buy CBD in the U.S.
Hemp-derived CBD products are widely available in gas stations, pharmacies, grocery stores, specialty wellness shops, and online retailers across most states. Licensed cannabis dispensaries sell CBD products derived from both hemp and marijuana, though dispensary access depends on your state’s cannabis laws.
One important caveat: the FDA has approved only one CBD medication, a prescription oral solution used to treat seizures associated with three specific conditions (Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex) in patients one year and older. That product, first approved in 2018, remains the only CBD formulation that has gone through the full federal drug approval process. Everything else on store shelves is sold as a supplement or wellness product without FDA evaluation for safety or effectiveness.
Types of CBD Products
CBD products generally fall into three categories based on what else from the plant is included:
- Full-spectrum CBD contains the full range of cannabis plant compounds, including other cannabinoids, terpenes, and essential oils, plus up to 0.3% THC. Some users prefer this because of the “entourage effect,” the idea that these compounds work better together.
- Broad-spectrum CBD is similar but with THC removed or reduced to trace amounts below 0.3%.
- CBD isolate is pure CBD with no other plant compounds. It typically comes as a crystalline powder and contains no THC at all.
CBD Legality Outside the U.S.
CBD is sold in most major international markets, but the rules vary significantly. In Europe, CBD is generally treated as a food supplement, and each country sets its own THC threshold. Germany, France, and the Czech Republic allow CBD products with up to 0.3% THC. The UK permits CBD with under 0.2% THC but requires brands to apply for a Novel Food authorization. Switzerland has the most permissive standard in Europe, allowing up to 1% THC.
Italy’s situation is more complicated: CBD is technically legal with THC between 0.2% and 0.6%, but two overlapping laws create confusion, and the government has pushed to ban products derived from hemp flower. Spain allows CBD only for medicinal purposes. The Netherlands permits CBD sales but, somewhat paradoxically, does not allow domestic CBD production.
In Canada, cannabis is fully legal for adult use, and CBD products are regulated under the same framework as other cannabis goods, meaning they’re sold through licensed retailers rather than the unregulated supplement market seen in the U.S.
CBD and Drug Testing
Standard workplace drug tests screen for THC, not CBD. Pure CBD isolate should not trigger a positive result. However, full-spectrum products contain small amounts of THC that can accumulate with regular use, and mislabeled products may contain more THC than advertised.
CBD itself clears the bloodstream quickly. After smoking cannabis, CBD was undetectable in blood within one hour in most participants tested. THC lingers much longer, especially in urine, which is why the real drug-test risk from CBD products comes from their THC content rather than the CBD itself. If passing a drug test matters to you, CBD isolate is the safest choice, and checking for third-party lab results on any product you buy adds another layer of confidence.