CBD comes from Cannabis sativa, specifically from varieties of the plant known as hemp. It’s produced inside tiny, mushroom-shaped glands on the surface of the plant’s flowers, then extracted and processed into the oils, tinctures, and other products you see on shelves. The journey from plant to product involves some interesting biology and chemistry worth understanding.
Hemp vs. Marijuana: Same Species, Different Chemistry
Hemp and marijuana are both cultivars of the same species, Cannabis sativa, but they’ve been bred over generations for very different chemical profiles. Hemp plants are rich in CBD and produce only trace amounts of THC, the compound responsible for a marijuana high. Marijuana cultivars, by contrast, are bred for high THC content.
The legal line between the two, at least in the United States, is drawn at 0.3% THC on a dry weight basis. The 2018 Farm Bill established this threshold: any Cannabis sativa plant or derivative containing no more than 0.3% delta-9 THC qualifies as hemp and is federally legal. Anything above that is classified as marijuana and falls under different regulations. Nearly all commercially available CBD is sourced from hemp.
Where CBD Forms Inside the Plant
CBD is manufactured in tiny, hair-like structures called glandular trichomes that cover the surface of cannabis flowers. If you’ve ever seen a cannabis bud up close, you may have noticed a frosty, crystalline coating. Those are trichomes.
Each glandular trichome has a stalk and a bulbous head. At the base of the head sits a cluster of specialized secretory cells called disc cells. These cells are the actual factories where CBD and other cannabinoids are built. Once produced, the compounds accumulate in a small storage cavity just beneath the outer skin of the trichome head, like a tiny reservoir of resin. The stalks of the trichomes have waxy, waterproofed walls that prevent this resin from leaking back into the rest of the plant.
These cannabinoid-rich trichomes are especially dense on the female plant’s reproductive organs: the bracts and small leaves surrounding the flowers. Major cannabinoids stored in trichome heads can account for over 15% of the female flower’s dry weight, making the flowers by far the most valuable part of the plant for CBD production. Leaves, stalks, and stems contain far less.
How the Plant Builds CBD
Cannabis doesn’t actually produce CBD directly. It first builds a precursor molecule called CBDA (cannabidiolic acid), which is later converted into CBD.
The process starts with two building blocks the plant synthesizes on its own. Through a chain of enzymatic reactions, the plant creates a compound called olivetolic acid, then attaches a chemical group to it to form CBGA (cannabigerolic acid). CBGA is the “mother cannabinoid,” the shared starting point for CBD, THC, and several other cannabinoids. A specific enzyme in hemp, called CBDA synthase, then converts CBGA into CBDA.
CBDA sits in the trichomes until heat enters the picture. When exposed to temperatures above roughly 100°C (212°F), CBDA sheds a small chemical group (a carboxylic acid) and becomes CBD. This heat-driven conversion is called decarboxylation. Lab experiments have shown that CBDA partially converts at temperatures as low as 80°C but requires around 139°C for complete conversion in a short time frame. In commercial CBD production, this step happens either during extraction or as a deliberate heating step afterward.
Where Hemp Is Grown
The European Union dominates global hemp production. In 2022, worldwide hemp output was an estimated 275,000 tons, and the EU accounted for more than half of that. France leads European production with about 19,400 hectares under cultivation, followed by Germany and the Netherlands. The United States became a significant producer after the 2018 Farm Bill opened the door to large-scale hemp farming, with major growing regions in states like Colorado, Oregon, and Kentucky.
How CBD Is Extracted From Hemp
Once hemp is harvested and dried, the CBD locked in its trichomes needs to be separated from the rest of the plant material. There are several ways to do this, but supercritical CO2 extraction has become the industry’s preferred method.
Supercritical CO2 Extraction
Carbon dioxide, the same gas you exhale, behaves differently under high pressure and moderate temperature. Push it past a specific threshold (around 74 bar of pressure and 31°C) and it enters a “supercritical” state where it acts like both a liquid and a gas simultaneously. In this form, CO2 can dissolve compounds out of plant material the way a liquid solvent would, but it penetrates plant tissue as easily as a gas.
In practice, dried hemp flower is loaded into an extraction chamber. Pressurized CO2 (typically around 250 bar and 37°C for maximum cannabinoid yield) flows through the plant material, dissolving the cannabinoids, terpenes, and other compounds from the trichomes. The CO2 carrying these dissolved compounds then moves into a separation chamber where the pressure drops. At lower pressure, the CO2 returns to a gas and releases the extracted material, which is collected as a concentrated oil. The CO2 itself is recaptured and recycled.
The appeal of this method is its cleanliness. CO2 is non-toxic, non-flammable, and leaves no residue in the final product. It also operates at low enough temperatures to preserve heat-sensitive cannabinoids. The main drawback is that CO2 extraction can sometimes yield lower total cannabinoid amounts compared to solvent methods, and the equipment is expensive.
Solvent-Based Extraction
Ethanol (alcohol) and hydrocarbon solvents like butane or propane are also used. Ethanol extraction is straightforward and efficient, but it pulls out unwanted compounds like chlorophyll along with the cannabinoids, requiring extra purification steps. Hydrocarbon methods using butane or propane can be highly selective, but they introduce safety risks because these gases are flammable and potentially explosive under pressure. Industrial-grade solvents may also contain impurities that end up in the extract if not properly purged.
Regardless of method, the raw extract typically goes through additional processing: winterization (chilling to remove fats and waxes), filtration, and distillation to concentrate the CBD and remove unwanted compounds. The result is either a full-spectrum extract containing CBD along with other cannabinoids and terpenes, a broad-spectrum extract with THC removed, or CBD isolate in its pure crystalline form.
Lab-Grown CBD
Scientists have also developed ways to produce CBD without growing a single plant. Using genetically engineered yeast, specifically strains of Saccharomyces cerevisiae (common brewer’s yeast), researchers have inserted the genes responsible for cannabinoid production into microbial cells. These modified yeast can convert simple sugar feedstocks into cannabinoid precursors and, with the right enzymes, into CBDA itself.
The concept works by swapping in the gene for CBDA synthase (the enzyme hemp uses to make CBDA) instead of the one for THCA synthase. The yeast then follows essentially the same biochemical pathway the plant does, just inside a fermentation tank rather than a trichome. This approach is still scaling up commercially, but it promises a consistent, environmentally controlled supply of CBD that doesn’t depend on agricultural land, weather, or growing seasons.