Short answer: CBD has a half-life of about 56 to 61 hours. Levels peak about 2.5 to 5 hours after a dose. People vary, so treat these as estimates.
CBD (cannabidiol) is one of the main compounds in the cannabis plant; unlike THC, it is not the part that causes a "high." It is sold in foods, products labeled as supplements, and cosmetics for many uses, but the only FDA-approved CBD product is Epidiolex, a prescription drug for seizures in three rare conditions.
Also known as: cannabidiol, Epidiolex, hemp extract, CBD oil.
The only FDA-approved CBD product is Epidiolex, an oral solution with 100 mg of cannabidiol per mL. Over-the-counter CBD products are not FDA evaluated; FDA tested some and found many did not contain the amount of CBD they claimed.
FDA's position: FDA has approved only one CBD product, Epidiolex, to treat seizures from Lennox-Gastaut syndrome, Dravet syndrome or tuberous sclerosis complex in people 1 year and older. FDA says it is illegal to market CBD by adding it to food or labeling it as a dietary supplement. In January 2023, FDA concluded that its existing rules for foods and supplements are not appropriate for CBD and said it would work with Congress on a new approach. The 2018 Farm Bill removed hemp from the definition of marijuana, but FDA says CBD products are still subject to the same FDA laws as other products.
Risks FDA lists: CBD can cause liver injury; this was seen in Epidiolex studies, including in people not taking other liver-affecting drugs, and was found through blood tests. CBD can change how other medicines work; the Epidiolex label lists interactions involving CYP3A4, CYP2C19 and other drug-processing enzymes. Using CBD with alcohol or sedating drugs raises the risk of drowsiness and injury. Animal studies showed male reproductive harm, including smaller testes and lower testosterone; what this means for people is not yet known. Common side effects are sleepiness, diarrhea or less appetite, and irritability or agitation.
NCCIH adds that over-the-counter products may contain more or less CBD than labeled and may contain THC. FDA says it is not known what happens with daily long-term use, what amount triggers the known risks, or how CBD affects pregnancy, breastfed babies or the developing brain. Talk to a clinician before using CBD, especially with other medicines.
The FDA Epidiolex label gives a plasma half-life of 56 to 61 hours after twice-daily dosing for 7 days in healthy people and a time to peak of 2.5 to 5 hours at steady state; a high-fat meal raised peak levels about 5-fold. These figures are for the purified prescription product; over-the-counter CBD products may behave differently.
Numbers shown are taken from the source above. Half-life varies from person to person.
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