Most of the science on CBD is related to humans, so when it comes to translating that data for pups, the truth is that there’s a degree of guesstimation involved.
However, CBD usage among pet owners is widespread and well-established, with many dogs having benefited from the anti-inflammatory powers of CBD for years.
Combine the science on humans with pet owner’s anecdotal reports, and you get a pretty reliable answer to the question of how long CBD remains active in a dog’s system: between four and twelve hours.
When discussing how a substance is active in the body, you’ll see a lot of talk about ‘half-lives.’ According to this explainer by California Northstate University, a half-life is “the length of time required for the concentration of a particular substance to decrease to half of its starting dose in the body.”
Drug half-lives matter for manufacturers and four-legged patients, because they help determine dosage. If you’re looking for a treatment that lasts all day, but you only want to administer it once, you’ll need something with an elimination half-life of at least twelve hours.
As this paper on drug design from The Journal of Medical Chemistry explains, a short half-life “may require more frequent dosing in order to maintain desired exposures and avoid unnecessarily high peak concentrations.
An overly long half-life, on the other hand, can a prolonged “accumulation and subsequent elimination,” meaning substances are constantly affecting the body.
The consensus on the elimination half-life of CBD in humans is between 18 and 32 hours, so anywhere from a day to a day-and-a-half.
This is when CBD is ingested orally. Another method of delivery will likely result in a speedier half-life.
Individuals’ ability to metabolize CBD will differ depending on factors like their age and previous exposure to CBD. Some studies have recorded half-lives as low as nine hours, while others put the figure as high as five days. But the majority of evidence suggests that a full 24-hour cycle is a good general benchmark.
Of course, those numbers relate to humans—so what’s the half-life of CBD oil for dogs?
The body of research is much thinner, meaning that numbers are less conclusive. But, we know that CBD interacts with via the same biological mechanism (the endocannabinoid system) in people and dogs. We also know that dogs have faster metabolisms than us, hence the concept of dog years. These pieces of information suggest that CBD is processed by dogs in a day or less.
Current studies back up this assumption. An older study out of Israel found a half-life of nine hours in dogs when CBD was given through IV, while a 2018 study from Frontiers in Veterinary Science puts the number at just over four hours for our four-legged friends.
The anecdotal evidence
The science is only one side of the coin, however. For a full picture, it’s important to see whether conclusions drawn in the lab match up with the reality of how CBD is being used by dogs and owners in everyday life.
It seems that most pet owners advocate for an eight-hour dosage—so, one or two lots of CBD per day. When, and how much, those dosages consist of is going to depend on the purpose of CBD treatment & the specific CBD oil.
Read: Our CBD dosage guide for dogs
Owners looking to maintain a consistent level of CBD in their dog’s system, should veer towards lower, twice-daily doses. Those looking to treat for specific incidents such as panic triggers may want to consider a single, more concentrated daily dose.