The market for CBD products has exploded in recent years, with the non-intoxicating cannabinoid turning up in everything from beverages to gummies to creams. Because it’s fat-soluble, CBD can hang around in your body for days, even weeks if you’re using it regularly. While CBD itself won’t turn up in drug tests, many CBD products contain THC—even when they claim not to—which does show up.
What is CBD?
Cannabidiol, popularly known as CBD, is a compound found in cannabis plants. It’s distinct from THC, the compound behind the euphoric intoxication—or “high”—produced by marijuana.[1] When present without THC, as it is in hemp, CBD has a calming effect without causing impairment.
The Food and Drug Administration (FDA) has approved a CBD-based medication for two epilepsy disorders. CBD has also been researched for and is used off-label for pain, anxiety, multiple sclerosis, insomnia, nausea and vomiting, and other conditions. In the United States, CBD derived from hemp, and containing less than 0.3% THC, is also legal as a cosmetic ingredient.[2]
In states where cannabis has been legalized, CBD is widely available in many different preparations (tinctures, capsules, edibles, creams, tongue sprays, and vaporizer sprays). However, you should ensure you’re not unwittingly buying a legal product high in THC.
How long does CBD take to kick in?
The amount of time it takes for you to feel the effects of CBD depends, among other things, on the way you took it.
- Inhaling: If you vape or smoke CBD, you’ll feel the effects as quickly as three minutes.[3]
- Sublingual: A popular way to take CBD is to place a drop of oil or spritz a spray under the tongue, where it’s absorbed through a mucus membrane within 30 seconds and passes into the bloodstream. You’ll feel the effects within 15 to 30 minutes.[4]
- Ingesting: If you swallow the CBD, whether in its oil form, in a capsule, or in an edible, it will be absorbed through the digestive system, a process that takes longer. You should expect to feel the effects of ingested CBD within one to three hours.[3] If you’ve eaten recently and your stomach is full, you’ll wait longer.
- Topical: The CBD in products like creams and lotions doesn’t penetrate the skin and reach the bloodstream. Instead, you feel the effects—including pain relief—only in the area to which it’s applied and within a few minutes.[4] The presence of hair or fat can reduce the effects and delay the onset.[5]
- Transdermal patch: Transdermal patches have additional ingredients to help the CBD penetrate the skin and enter the bloodstream. They’re usually designed for slow absorption and you may not notice effects for several hours and peak effects may be delayed by up to a day.
How long do the effects of CBD last?
The duration of CBD's effects—including calmness and pain relief—can be anywhere from 30 minutes to 48 hours, depending on the method of administration.
- Inhaling: effects last 30 minutes to an hour
- Sublingual: two to four hours
- Ingesting: 4 to 6 hours
- Topical: 5 or more hours
- Transdermal patch: 24 to 48 hours[5]
The duration of the effects also depends on the dosage, your metabolism and body composition, and other factors specific to methods of administration such as your stomach contents and the hair on your skin.
How long does CBD stay in your system?
One study found that the half-life after a single dose of CBD—the amount of time it takes for your body to eliminate half the drug—is 18 to 32 hours.[6]
CBD, like other cannabinoids, is fat-soluble, which means it can be stored in your body’s fat tissue and sticks around longer than water-soluble drugs such as cocaine.
Regular use causes CBD to accumulate in your fat cells, to be slowly released and cleared, sometimes over weeks. A study of 14 patients with Huntington’s disease who were given 700mg of CBD per day for 6 weeks—a much higher dose than is typical—measured the half-life at between two and five days.[7]
Because it takes the body five and a half half-lives to eliminate a substance, these studies suggest CBD may be present in the body from four to 20 days. However, this can vary dramatically between people and situations.
Factors that affect how long CBD stays in your system
The length of time CBD stays in your body depends on several factors:
- Dosage: One study found that 1.35mg of CBD (a tiny dose) was detectable in the body for just six hours, while higher doses were detectable for longer.[8]
- Frequency of use: CBD accumulates in fat cells before being cleared from the body so more regular use means it will be detectable for longer.
- Your body fat: The more fat tissue you have, the more CBD can be stored in the body.
- Method of administration: The way you’ve taken the CBD influences how quickly it’s metabolized and eliminated from the body. A review found that the half-life of CBD taken as an oral spray was just 1.4 to 10.9 hours, while it was 24 hours after an intravenous infusion, and 31 hours after smoking.[9]
- When and what you’ve eaten: The presence of high-fat food in your stomach increases the body’s absorption of CBD and reduces the clearance rate. On the other hand, if you take CBD on an empty stomach, the body will absorb less and remove what it does absorb more quickly.[10]
- Liver function and the presence of medication processed by the liver: CBD is metabolized by the liver, using the same enzymes that break down most prescription drugs. CBD metabolism may be slowed if you’re taking it concurrently with medication and if your liver function is impaired.
Does CBD show up in drug tests?
Drug tests don’t specifically screen for CBD as it’s not intoxicating and isn’t an illegal substance. However, many CBD products contain THC, often more than is stated on the package, due to poor oversight of the industry.
One study of nearly 300 CBD-containing food products available on the German market found that 10% contained levels of CBD above the threshold for causing intoxicating effects.[11]
Even products that claim to be free of THC may actually contain traces of it. The manufacturers may be outright lying or may not have subjected their products to third-party testing.
You should therefore take CBD with caution if you’re going to face drug testing.
Can you flush CBD out of your system?
There’s typically no reason to flush CBD out of your system as it itself won’t show up in drug tests. However, if you’re worried about the presence of THC in your CBD products, you may be eager to remove it from your body as soon as possible.
There’s no reliable and safe way to expedite your body’s removal of cannabinoids. However, taking them as oral sprays and on an empty stomach and not with a high-fat meal can mean your body clears them more quickly.