U of M researchers compared CBD absorption in patients on an empty stomach v. a standardized fatty breakfast. Bioavailability refers to the degree and rate at which a substance is absorbed into your bloodstream. Read more on how dosage and consumption method can affect how much cannabis your body uses. Not all CBD is the same. Discover the differences between CBD delivery forms and the pros and cons of each. Learn how to choose the best CBD form for you.
High fat foods can increase CBD absorption into the body
While oral cannabidiol (CBD) capsules were approved by the U.S. Food and Drug Administration (FDA) for use in patients with seizures in 2018, very little was known about the effect of food on CBD absorption.
A University of Minnesota study, published in Epilepsia , examined whether eating high-fat foods after taking CBD increased the body’s absorption of CBD. The study tested whether fasting or a high fat meal has an effect when cannabidiol oral capsules were taken by patients.
To find out what effect a fatty meal would have on CBD absorption, the research group measured CBD concentrations in epilepsy patients at the MINCEP Epilepsy Care clinic who were taking 99 percent pure CBD capsules. Concentrations from patients who took CBD on an empty stomach and a standardized fatty breakfast (i.e. breakfast burrito) were compared.
“The type of food can make a large difference in the amount of CBD that gets absorbed into the body. Although fatty foods can increase the absorption of CBD, it can also increase the variability as not all meals contain the same amount of fat,” said Angela Birnbaum , a professor in the College of Pharmacy and study co-author.
“Increases in the amount of the CBD dose being absorbed into the body can also lead to lower medication costs,” said Ilo Leppik , study co-author, a professor in the College of Pharmacy and an adjunct professor at the Medical School.
The study found:
- CBD exposure is vastly increased when CBD is taken with high fatty foods;
- when compared to fasting, taking CBD with food increased the amount of CBD in the body by four-times and the maximum amount recorded in the participants’ blood by 14-times;
- no cognitive differences were identified, which is consistent with previous studies.
“For epilepsy patients, a goal is to maintain consistent blood concentrations of drug,” said Birnbaum. “This study shows that CBD concentrations could vary significantly if patients take it differently, sometimes with or without food. Variations in blood concentrations could leave a patient more susceptible to seizures.”
This research was funded by the Epilepsy Foundation of America, the Patricia L. Nangle Fund, and a gift from a grateful family. Additional U of M study authors include Susan Marino, College of Pharmacy, Masonic Cancer Center; Christopher Barkley, College of Pharmacy; Rory Remmel, College of Pharmacy, Masonic Cancer Center; Michaela Roslawski, College of Pharmacy; U of M Twin Cities student Ashwin Karanam; and Aden Gramling, University of Minnesota Physicians.
Angela Birnbaum , PhD, FAES, is a professor in the College of Pharmacy. Her research focuses on the variability of drug concentrations and response in topics related to the elderly, pregnant women, children, and drug addiction. Dr. Birnbaum’s research includes investigation of epilepsy medications including medical cannabis.
Ilo Leppik , MD, is a professor in the College of Pharmacy and an epilepsy specialist at the University of Minnesota Physicians Epilepsy Care. His research focus includes neurology and epilepsy — specifically around epilepsy in older adults, canine status epilepticus, and treating epilepsy with cannabis.
About the College of Pharmacy
Founded in 1892, the University of Minnesota College of Pharmacy is the only pharmacy school in Minnesota, with campuses in the Twin Cities and in Duluth. The College of Pharmacy improves health through innovative education, pioneering research and interdisciplinary practice development that attends to the diverse needs of the people of Minnesota and the world.
Most THC and CBD oil goes to waste in your body—here’s why
If you knew that only 6% of your CBD gummies would enter your bloodstream to do their job, would you still purchase them? Amid the current frenzy surrounding cannabis and its therapeutic benefits, it’s easy to gloss over the bioavailability of cannabis products.
Bioavailability refers to the degree and rate at which a substance is absorbed into your bloodstream to be used where needed. Physiological processes and consumption methods can affect cannabis absorption, rendering its effects somewhat hit-and-miss.
It’s critical to get clued up about bioavailability in order to maximize the medicinal potency of cannabis. The more bioavailable your cannabis, the lower the quantity of the plant you need to reap its benefits.
What factors influence cannabis bioavailability?
The surge in cannabis popularity can be partly attributed to the range of consumption methods available. Edibles and tinctures can have less of the stigma traditionally associated with joints. However, when cannabinoids such as CBD and THC are ingested in oil form—oil is also used to make edibles—their bioavailability becomes compromised.
CBD and THC oils resist absorption into the bloodstream because the human body is up to 60% water . Basic science—and salad dressing—dictates that oil and water do not mix, and the same is true for cannabis oil and the human body.
“Cannabinoids are fat-loving molecules and have to traverse a cellular environment that is aqueous or watery,” explains Dr. Patricia Frye, a member of the Society of Cannabis Clinicians and chief medical officer at Hello MD . When cannabis is consumed as an oil, the onset of effects can become delayed and bioavailability limited.
Another phenomenon that limits oil-based cannabis extracts from reaching the bloodstream is the first-pass effect. When cannabis is ingested orally, it is absorbed in the gastrointestinal tract and transported via the portal vein to the liver, where it is metabolized. As a result of this process, only a limited quantity reaches the circulatory system. Since cannabis oil is often taken orally, its efficacy can be hindered.
Are some cannabinoids more bioavailable than others?
There has been some investigation into CBD, THC, and less into cannabinol, or CBN. Studies have shown that the bioavailability of cannabinoids depends on the method of delivery.
When applied as a topical ointment or transdermal patch, CBD can penetrate the tissue ten times more effectively than THC. The same is true of CBN.
THC, however, is more bioavailable than CBD when administered orally or delivered via the lungs. A clinical study found that concentrations of THC in the bloodstream appeared 30-50% higher than CBD following oral delivery as a sublingual spray.
However, the bioavailability of THC is still limited when consumed orally, averaging only 4-12%. When smoked or vaped, the bioavailability of THC leaps to an average of 30%.
Which methods of cannabis consumption optimize bioavailability?
Some of the most common and convenient cannabis products, such as capsules, soft gels, tinctures, and edibles, limit bioavailability due to the first pass through the liver. “With edibles, absorption is slow, unpredictable, and highly variable,” says Frye. “Only about 6% of the dose is absorbed. The onset of action can be as long as 6 hours; it’s very easy to take too much, and the effects can last as long as 20 hours!”
Oral administration lasts longer than smoking, eliminating the need for frequent dosing. Oral methods also avoid irritation to the airways and the risk of malignancies associated with smoking or vaping.
That said, inhaling cannabis guarantees increased bioavailability because molecules are transported by vapor particles directly to the alveoli in the lungs. This allows cannabinoids to rapidly enter the bloodstream without being metabolized by the liver.
Another lesser known method of administration is intranasal delivery, which enables cannabinoids to be easily absorbed with a rapid onset of 10 minutes or less. “Intranasal methods are highly bioavailable at 34-46%,” says Frye. “It’s a particularly helpful mode of delivery for patients who are having a seizure or for patients trying to abort an impending seizure or migraine.”
Transdermal patches can be super effective at targeting localized or systemic pain. They allow for a steady infusion of active ingredients to the delivery site, so the patient is unlikely to experience spikes of THC in the bloodstream.
Finally, nano-emulsions and micro-emulsions can dramatically increase the stability and bioavailability of cannabinoids. These novel formulations use nanotechnology to offer up to 100% bioavailability. Frye cautions, however, that the research is still scarce. “We don’t know the full extent of how these manipulations affect cannabinoid activity at the cellular level,” she says.
What tips or tricks can help increase bioavailability?
One method that boosts the absorption of edibles is to combine cannabis product with fats. Frye recommends combining edibles or tinctures with healthy fats such as guacamole, hummus, or dark chocolate. If you’re feeling less virtuous, however, ice cream works as a treat. The same goes for alcohol-based tinctures.
For those who smoke or vape, bioavailability can be enhanced by minimizing sidestream loss and increasing the number of puffs. “Using a desktop or handheld vaporizer with flower will eliminate sidestream losses,” Frye advises. If you think you get more bang for your buck by holding your breath, think again. “There is no evidence supporting holding one’s breath for more than 10 secs,” says Frye.
Some final words of advice from Dr. Fyre, for those looking to optimize cannabis bioavailability: “The most cost-effective way to use cannabis is not to use more than you need. Less is more,” she says. Due to its biphasic nature, excessive dosing may exacerbate the symptoms you’re trying to alleviate.
CBD Bioavailability: What Does it Mean Why is it so Important?
Not all CBD is the same. Discover the differences between CBD delivery forms and the pros and cons of each. Learn how to choose the best CBD form for you.
In this article, we explore the various delivery methods for CBD (cannabidiol), including oral, inhaled, mucosal, transdermal, and intravenous routes.
We’ll discuss what the current science tells us about each method and their relative advantages and disadvantages in practical use.
We’ll also survey some of the important factors that affect CBD absorption and metabolism. And you’ll learn how you can best manage these factors so you can choose the ideal delivery form and dosage depending on what you’re looking to get out of the use of CBD.
This is a big topic, so let’s get straight into it.
Table of Contents
- Oral CBD: Capsules, Oils, and Edibles
- 1. Health Conditions
CBD offers great benefits for health and healing. Its high safety profile and non-addictive nature make it an appealing alternative to many conventional drugs.
But, in order to be effective, CBD has to reach your endocannabinoid system. This means it first needs to be absorbed into your bloodstream, a concept known as bioavailability.
Once there, it has to stay in circulation long enough to be delivered to the organs and tissues where it is needed.
So, how much of the CBD you take actually gets absorbed and used?
That depends on a process known as pharmacokinetics (how compounds are processed by the body).
In short, pharmacokinetics refers to the sum of your body’s mechanisms for absorption and elimination, the characteristics of CBD itself, and numerous external factors that can either help or hinder the way you assimilate and use CBD.
Additionally, the route of entry, or delivery method, has a lot to do with how much and how quickly CBD enters the bloodstream.
Oral CBD: Capsules, Oils, and Edibles
Oral CBD formulations, such as CBD oils and tinctures, capsules, gummies, chocolates, other edibles, and beverages are among the most popular ways to consume CBD.
However, oral CBD has the lowest bioavailability of all delivery forms.
On average, ingested CBD has a bioavailability of between 6-19% [2, 3, 4].
One reason for this is that CBD is not readily absorbed when ingested and as a result, most of it is excreted without exerting any effects.
This is due to the fact that CBD is fat-soluble (as opposed to water-soluble), which makes it a challenge for the body to absorb.
Additionally, digestive acids and enzymes destroy a large percentage of CBD before it has a chance to be absorbed. And the small amount that gets through the intestinal wall is subject to being metabolized by the liver before it reaches the rest of the body.
The half-life of oral CBD, i.e. the amount of time it takes for half of the CBD to leave the bloodstream, may be faster than other delivery methods. Half-lives from 10 to 17 hours have been reported for high dosages between 750 mg and 1500 mg .
Peak levels of oral CBD tend to be lower than other delivery forms.
In one experiment, cookies infused with 40 mg of CBD produced peak blood CBD levels between 1.5 and 3 hours after ingestion .
However, the low absorption of oral CBD may be offset by certain advantages — such as a longer duration. A laboratory animal study found the average amount of time an orally consumed CBD molecule stays in the body, known as the “mean residence time”, was 4.2 hours.
By contrast, the mean residence time for injected CBD, in the same study, was 3.3 hours .
Oral CBD has also been found to lead to higher brain levels when compared to inhalation methods in animal studies .
Bioavailability of CBD: Vaping vs Oral Consumption
Inhaled CBD: Vaping and Smoking
Inhalation is an efficient way to consume CBD because it bypasses the digestive tract and liver allowing CBD to be readily absorbed through the thin membranes that line the air sacs of the lungs (alveoli) where it enters directly into the bloodstream.
There are several ways to inhale CBD:
The most basic inhalation form is smoking.
In this case, the hemp cigarette contains unprocessed CBD-rich hemp buds (as opposed to high-THC cannabis). Smoking has a bioavailability of 31% and a single CBD cigarette containing about 19 mg of CBD can produce peak blood levels within 3 minutes .
The half-life of smoked CBD averages 31 hours.
The downside to smoking is that it produces combustion by-products which can irritate and, in some instances damage the lungs. These include fluorene, pyrene, acrylonitrile, and acrylamide .