CBD is becoming increasingly popular. And with more and more people using CBD supplements, many have questions about how long CBD products remain in the body after application. Below we’ll explain how the body processes CBD, its half-life, and much more.
CBD works primarily by interacting with the endocannabinoid system, a regulatory system that keeps the body working at its best. Unlike other cannabinoids, CBD doesn’t bind with endocannabinoid receptors directly. Instead, it interacts with a wide variety of receptors around the body to deliver its unique effects.
CBD can be taken in a variety of different ways, with method of administration playing a key role in how the compound is metabolised. If you take CBD orally, for example, it needs to pass through the digestive system. When taken sublingually (under the tongue) or inhaled through a vaporizer, however, CBD can bypass the digestive system and get to work faster.
Once absorbed into the body, CBD is transported to the liver where it is metabolised into a variety of compounds that your cells can use. This metabolism is carried out by a group of enzymes known as cytochrome P450, which are also responsible for metabolising around 60% of all medications on the market.
From the liver, CBD metabolites are transported around the body, where they may interact with a wide variety of receptors.
In 1991, a group of researchers from the College of Pharmacy at the University of Arizona Health Sciences Center tested CBD on 14 patients with Huntington’s disease. The patients were given doses of around 700mg of CBD per day for 6 weeks. Note that these doses are much higher than a standard recommended dose.
The researchers then used an assay to quantitatively measure the presence and functionality of CBD in the participants’ bodies. Over the 6 weeks of treatment, CBD levels measured in the patients’ plasma ranged from 5.9–11.2ng/ml. One week after treatment came to an end, the average blood-plasma level of CBD was about 1.5ng/ml. After that, CBD was virtually undetectable in the body. Based on these results, the researchers determined CBD’s half-life to be between 2–5 days.
Half-life is the term used to measure the amount of time a compound stays in the body. It is gauged by measuring blood plasma for metabolites of the compound in question. From the plasma, drug metabolites are either removed from the body or translocated to another type of bodily fluid.
Half-life is typically measured by administering a single dose of a compound, then testing blood plasma for traces of the drug at regular intervals. The amount of the drug in the plasma will usually increase, reach a peak, and then start to decline. Half-life refers to the amount of time it takes for the plasma concentration of the drug to decrease by half.
Unfortunately, the exact half-life of CBD isn’t 100% clear. The study mentioned earlier, for example, suggested that CBD has a half-life of 2–5 days, but this study used extremely high daily doses of CBD (700mg, which is equivalent to an entire 30ml bottle of 2% CBD oil).
Another study published in 1986 in the journal of Biomedical and Environmental Mass Spectrometry suggests that the half-life of CBD may only be between 18 and 35 hours, depending on the method of administration.
The study featured 5 young men who were given roughly 20mg of CBD either intravenously or via smoking. Following administration, researchers monitored the participants’ blood-plasma levels for 72hrs. Based on their findings, the researchers established that CBD has a half-life of around 27–35hrs when smoked, and 18–30hrs when administered intravenously.
Whenever talking about the metabolism of any compound, it’s important to realise that everyone’s body is a little different, and there are a number of factors that can influence your body’s ability to process compounds such as CBD.
- Body weight
- Efficiency of your metabolism
- Method of consumption
- Amount of CBD consumed
- Purity and strength of the oil/supplement you’re using
- Bioavailability of CBD (which can change depending on the route of administration)
CBD is a very unique and complex compound that can affect everyone slightly differently. Unfortunately, studies have not yet been able to pinpoint the exact half-life of cannabidiol. Based on the two studies mentioned above, the half-life of CBD can be estimated to be between 18 and 35 hours. Other studies not mentioned here suggest that the half-life of a single dose of CBD may be around 1–2 days.
However, remember that these are ball-park figures. As we mentioned earlier, a lot of different factors can influence the rate at which your body processes and metabolises compounds like CBD. However, until further studies look into the half-life of cannabidiol, these figures are the closest we've got—for now.