How Long Does CBD Last? [A Timeline of Your System]
CBD is now taken all over the world as both a medicinal aid and as a relaxant, able to combine the medical properties of THC without its intense psychoactive high.
CBD is becoming so prolific that some people are finding themselves failing drug tests based on their CBD usage. This is usually because tests carried out by employers are focused primarily on cannabinoid levels, rather than just on THC. Most CBD oils (assuming they’re “full spectrum”) will contain some small, trace amounts of THC, usually up to 0.3%. This is sometimes sufficient to trigger a false positive on a drug test.
This alone makes it incredibly important to figure out how long CBD lasts within your body. However, even without having to worry about the results of a test, it’s useful to know how long a substance will exist inside you.
hether this is to figure out how long until you can take another dose, or just because it’s just important to understand your own body, everyone should be aware of the longevity of drugs within their body.
So, how long does CBD last? Well, to get started, we need to understand CBD in general, as well as how it enters our system in the first place.
How CBD Works
CBD, or cannabidiol as it’s more properly known, is one of the major cannabinoids within the Cannabis sativa plant. Unlike its fellow cannabinoid THC, CBD is entirely non-psychoactive, meaning you receive no high whatsoever when you imbibe it.
CBD interacts with your Endocannabinoid System (ECS), a health system that exists throughout the human body and in all other mammals as well. That’s right, even dogs have one.
Within the ECS, there exists receptors known as the CB1 and CB2; these receptors are triggered by cannabinoids, thereby creating effects in the human body based on both their location and the intensity of the dosage.
The CB1 receptors are located primarily within the brain, as well as throughout the central nervous system, whereas the CB2 receptors are more liberally spread throughout the body. The CB1 receptors are partly responsible for the release of important neurochemicals such as serotonin or melatonin, as well as being able to influence the sensation of pain. The CB2 receptors, meanwhile, are responsible for healthy cell regeneration and functions like the inflammation response.
This varied capacity of the ECS means that cannabinoids like CBD can influence a great deal of different functions and issues within the human body.
For example, CBD is heavily tied to the inflammation response, allowing users to consume CBD so as to essentially shut off the inflammation response and prevent painful conditions like arthritis from causing pain, as evidenced in this landmark study by Carrier et al.
So, now that we understand what CBD is and how it interacts with the body, we need to learn about how CBD is actually taken in by the body, so as to properly understand how long it lasts.
How the Body Absorbs CBD
CBD is generally put in the body via two common methods – ingestion or inhalation.
In the case of inhalation, the user smokes the CBD as a CBD-rich cannabis or vapes it using an e-cigarette. When you do the latter, the CBD is mixed with water vapor and is breathed in through the respiratory system, eventually entering the lungs.
Once it’s there, the bloodstream that travels through the lungs will carry the CBD out of the water vapor in the same manner that it takes oxygen molecules from the air.
This will then carry the CBD throughout your system using the highways of the body – the circulatory system.
A very similar process happens when you imbibe orally.
If you take CBD oil or an edible, the CBD is digested in the stomach, entering the digestive tract and working its way through the intestines.
Once there, the bloodstream is able to carry away the CBD in much the same way it does with the lungs, only it needs to struggle against the flow of the digestive system.
One interesting difference between the two is that, if you consume CBD orally using an oil, you have a good chance to be able to get even more CBD out than you might expect thanks to something called “Intestinal Lymphatic Drug Delivery”.
Intestinal Lymphatic Drug Delivery can occur when you ingest CBD oil using an oil that is high in saturated fats, like coconut oil. When you do this, the oil can become stuck in the intestinal walls, stopping it from moving down the digestive tract as quickly as it might normally.
This allows the bloodstream more time to remove the CBD and carry it to its final destination. One study by Hyeji Ahn and Ji-Ho Park for the journal of Biomaterials Research found that this increased the bioavailability of CBD, so much so that they are exploring options to try and ingest other drugs using this same system.
Regardless of your preferred method of CBD intake, it all ends up in the same place in the end: The liver.
CBD & Your Liver
Once the CBD has been carried away by the bloodstream, it will take it to your liver.
Once there, it is broken down in much the same way as any other substance is destabilized and made into useable materials. An enzyme called Cytochrome P-450, usually known as CYP450, is the primary enzyme that breaks it down into useable materials and allows your body to utilize the CBD.
Once it’s broken down, it can begin to affect the body’s ECS because it enters the bloodstream.
One interesting thing to note about CYP450 is that its effectiveness can be reduced or entirely shut down if you eat certain foods, such as grapefruit or watercress. This can cause a reduction in actual drug efficacy, meaning the drug just sits around in the liver not doing much.
Well, now we know how CBD is actually entered into the body’s systems and utilized, how long does it actually last? What controls the rate of degradation for CBD?
CBD Length in the Body
CBD’s ability to exist within the human body is better described as CBD’s half life. The half life of a substance is the time it takes for the efficacy and total atomic presence to be reduced by exactly one half.
This is surprisingly easily measurable, as scientists can simply keep track of the amount of CBD within a host through rigorous experimentation, likely on some very relaxed, if a little unfortunate, rats. Unfortunate, because they were likely dissected.
The half life of CBD is defined by Welty, Luebke and Gidal in their study for the Journal of Epilepsy Currents as roughly 1 to 2 days. This is further clarified refined in Devinsky et al.’s study for the International League against Epilepsy, wherein the researchers peg the half life of CBD to between 18 and 32 hours.
This means that the effectiveness of CBD within your body diminishes by half after this period. However, doctors generally use the half life time of a substance as the same as it being fully removed.
This is because, though the substance has only been depleted by half, once it reaches that point of atomic distillation, it ceases to be able to affect the body’s systems in any meaningful way.
What this means is that, despite the half life being generally at least a day, your CBD prescription will still likely say to take multiple doses a day.
The same happens with doses of Paracetamol; you generally take the drug every 4 hours, no more than 4 times a day, yet the half life of the substance is actually 4 hours.
This means that, in a purely mathematical sense, after 16 hours of 4 doses of 1 gram of Paracetamol, you will actually have a total of 1875 mg of Paracetamol in your system. Weird, right?
Basically, whenever you see “half life” when referring to a substance within your body, consider it to be the same thing as essentially “completely gone”.
However, for the purpose of drug testing, depending on the intensity of the drug test, they might be able to still detect that level of cannabinoids within your body.
CBD is a cannabinoid, which means it is barred by the same rules for all cannabinoids within the human body, namely that it will degrade within 18-32 hours. However, THC degrades at basically the same rate, meaning your risk of detection from a drug test remains the same depending on the intensity of the drug test.
However, the actual effects of CBD degrade almost completely at the half life point. If you’re considering the length of CBD for the purpose of figuring out the safety of your dosage frequency, you can rest assured that your prescription will likely know what it’s talking about.
Though it might seem strange, considering it’s called half life, CBD loses almost all of its effectiveness right away.
So, to answer the question of how long CBD lasts, it’s about a day. With some addendums.
Nothing’s ever simple, is it?