Millions of people are taking CBD oil and other CBD products to help with everything from anxiety to workout recovery. But if you don’t use them properly you can end up spending hundreds of dollars without any noticeable results.
It’s largely because CBD is a fat-soluble compound that’s difficult for our bodies to absorb. That’s why it’s important to understand the concept of bioavailability and how it relates to CBD.
In this article, we’ll cover how cannabidiol is absorbed through different methods and suggest evidence-based tips for making CBD more effective.
Table of Contents
- What is CBD Bioavailability?
- CBD Administration Routes
- Tips to Maximize CBD Absorption & Effects
- A Word on Nano CBD
- Summing Up: Increasing CBD Bioavailability
What is CBD Bioavailability?
Written as a percentage, bioavailability is the portion of a drug that you took that is actually absorbed into your blood (1).
For example, when you take a 50 mg CBD capsule, your body doesn’t absorb and use all of that 50 mg. Research suggests that CBD’s oral bioavailability can be as low as 6%, which means you’d only be getting 3 mg of that initial 50 mg dose (2).
Meanwhile, if the same 50 mg was injected into your veins, it would have a bioavailability of 100% because all of the CBD goes directly into your bloodstream.
Higher bioavailability means you have to take less CBD to get the effects you’re after and can mean the difference between seeing benefits and seemingly no change. That’s why it’s important to understand how the bioavailability of CBD varies depending on the way you take it.
CBD Administration Routes
The vast majority of people use CBD in one of four administration routes:
- Oral: swallowing CBD
- Sublingual: putting CBD under your tongue
- Inhalation: smoking or vaping CBD
- Topical: applying CBD to your skin
Here’s a look at the differences in bioavailability between these four:
Made popular by vitamins and other supplements, the oral method involves ingesting CBD capsules, tablets, gummies, and other edible products (or even pure CBD powder). While this route is easy and convenient, it also has the lowest bioavailability out of any administration route.
When you ingest CBD, you will only absorb 6-24% of it (a range that depends heavily on whether the CBD was taken alongside fats; more on that later) (2).
That’s because of first-pass metabolism — the reduction in drug concentration that happens in the digestive system, before the CBD can reach your bloodstream (3). In particular, much oral CBD is lost in the liver before it reaches systemic circulation.
The sublingual method means putting CBD under your tongue. This is the route used by CBD oil, but you can also use CBD sprays, sublingual strips, lozenges, and even pure CBD powder.
Since the mucous membranes under your tongue are rich in capillaries (tiny blood vessels), the CBD is absorbed directly into the blood, bypassing the digestive tract. As a result, the sublingual bioavailability of CBD is significantly higher than oral (4).
The sublingual route is arguably the most effective CBD administration method because it combines good bioavailability with relatively fast and long-lasting effects and easy dosage control.
Although there isn’t much research data on the exact bioavailability of sublingual CBD, we know that CBD taken intranasally as a spray has a bioavailability of 34-46% (5). Since this administration route is similar to sublingual (your nose also contains mucous membranes rich in blood vessels), we can use it as a rough estimate for CBD’s sublingual bioavailability.
Inhaling CBD means smoking hemp flower or vaping CBD e-liquid. Similar to the sublingual route, this method has fairly high bioavailability. One study found that the bioavailability of smoked CBD was about 31% (range of 11 to 45%) (6).
Another advantage of inhaling CBD is that the effects are nearly instant, making it an excellent option when you need immediate relief. But it does last less than the sublingual route — about 1-2 and a maximum of 4 hours (7).
Applying CBD to your skin is a little different because it’s only going to act on the specific area you applied it to.
The only exception to that is transdermal formulations which are designed to absorb through your skin and into the bloodstream, which means they can have comparable effects to other methods (8). However, these formulations are relatively new and there’s no way of knowing if a product that claims to be transdermal actually works.
Tips to Maximize CBD Absorption & Effects
As we can see, one easy way to make CBD more effective is to opt for sublingual or inhaled products over oral formulations like capsules or gummies. But there’s a lot more to it than that. Here are some more evidence-based tips to get the strongest effects out of CBD.
Use Full-Spectrum Products Over Pure CBD
Full-spectrum CBD extracts contain a complete range of beneficial hemp cannabinoids and terpenes.
These compounds work synergistically to produce the “entourage effect”, making full-spectrum CBD products more beneficial than pure CBD isolate. For example, research suggests that terpenes may help cannabinoids cross the blood-brain barrier, enhancing their effects (9).
According to one 2018 paper, full-spectrum, CBD-rich extracts were about four times more potent than pure CBD (10).
Take CBD with Fat
If you’re taking CBD by mouth it’s recommended to have a high-fat meal first. CBD is a fat-soluble compound, so fats help your body absorb it (which is why CBD oil is the most popular way to use CBD).
In fact, a 2019 study showed that taking CBD within 30 minutes of a high-fat meal (breakfast burrito containing 500-600 calories of fat) versus an empty stomach increased its bioavailability by four times — from only 6% to 24% (11).
This tip is less important if you’re taking CBD orally in a form that already contains fats, such as softgels or brownies. But since the amount of fat in these products isn’t that high, you’re still likely to see increased absorption if you take them after eating high-fat foods.
We even recommend this tip for CBD oil because you’re still going to absorb some of the CBD orally after you hold it under your tongue and swallow it. But again, the benefit is going to be smaller compared to taking a product without any fats.
Follow Proper Technique
Another easy way to increase CBD bioavailability is to follow the proper technique for your chosen administration method.
The best way to make CBD oil work better (or any other CBD product that you take sublingually) is to hold it under your tongue for as long as possible. Although most products recommend holding it for 30-60 seconds, holding it longer is better because more of the CBD will have time to absorb.
We recommend holding CBD under your tongue for at least 3 minutes or even longer. If holding it under your tongue gets uncomfortable, you can also hold CBD next to your cheek or swish it around.
Although targeted studies are lacking, research suggests that your breath depth, how long you hold the smoke or vapor, and even vaporizer temperature can impact inhaled cannabinoid bioavailability (12).
You can follow one of the two main methods: direct-to-lung (inhaling vapor or smoke directly into your lungs) or mouth-to-lung (inhaling into the mouth first and inhaling again into the lungs). As a general recommendation, holding for at least a few seconds may be ideal.
As for CBD vaping temperature, again, there isn’t a whole lot of evidence. Your best bet is to use a device specifically designed for vaping CBD.
If you’re using a proper vape mod, you can experiment with a range between 160-230°C (320-446°F); the former is the lowest temperature at which CBD starts to vaporize, while the latter is the optimal temperature for vaping CBD reported by a 2014 study (13).
If you’re applying CBD topically in the form of creams, lotions, oils, and other products, the standard rules apply: make sure your skin is dry and massage it in to ensure optimal absorption.
Use Piperine Or Other Absorption Enhancers
Another less-common tip for oral CBD is to use bioavailability enhancers: compounds that help your body absorb supplement ingredients (14).
The best-known example is piperine, a natural compound found in black pepper. It’s frequently added to curcumin and other dietary supplements to enhance their absorption.
A 2020 study in rats found that piperine increased the oral absorption of CBD by 2.5 times (15). If you want to give this a try, your best option is to buy a separate piperine supplement, which is relatively cheap.
A Word on Nano CBD
One last thing to mention is nanotechnology, which holds the greatest promise of increasing the oral bioavailability of CBD and indeed all drugs. Research into nanoformulations for CBD is ongoing and showing promising results.
For example, a 2019 study of a CBD nanoemulsion reported greater oral absorption than regular CBD oil in rats (16). Similarly, a 2018 study in healthy men reported faster absorption and 31% greater CBD bioavailability from a THC/CBD nanoformulation compared to Sativex (a 1:1 THC/CBD drug) (17).
But the problem with CBD nanoformulations is that they’re not yet widely available in commercial products. Even though you can find many companies advertising “water soluble” and “nano CBD” there isn’t much evidence to prove that these products have enhanced bioavailability.
Summing Up: Increasing CBD Bioavailability
We hope these tips and explanations help you get the most out of CBD. Of course, don’t forget that dosage also plays a role. If you take a small dose of CBD it might not matter that you’re doing everything right to increase its bioavailability.
Sometimes, you simply need to up your CBD dosage. The best approach is to “start low and go slow” (18). Begin with the amount suggested by your product, give it at least two hours to see the effects, and gradually raise the dosage over time if needed. Repeat this until you find just the right amount that gives you the desired effects.
- Price, Gary, and Deven A. Patel. “Drug bioavailability.” StatPearls [Internet]. StatPearls Publishing, 2021.
- Perucca, Emilio, and Meir Bialer. “Critical aspects affecting cannabidiol oral bioavailability and metabolic elimination, and related clinical implications.” CNS drugs 34.8 (2020): 795-800.
- Herman, Timothy F., and Cynthia Santos. “First pass effect.” (2019).
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- Pamplona, Fabricio A., Lorenzo Rolim Da Silva, and Ana Carolina Coan. “Potential clinical benefits of CBD-rich cannabis extracts over purified CBD in treatment-resistant epilepsy: observational data meta-analysis.” Frontiers in neurology (2018): 759.
- Birnbaum, Angela K., et al. “Food effect on pharmacokinetics of cannabidiol oral capsules in adult patients with refractory epilepsy.” Epilepsia 60.8 (2019): 1586-1592.
- Bruni, Natascia, et al. “Cannabinoid delivery systems for pain and inflammation treatment.” Molecules 23.10 (2018): 2478.
- Solowij, Nadia, et al. “A protocol for the delivery of cannabidiol (CBD) and combined CBD and∆ 9-tetrahydrocannabinol (THC) by vaporisation.” BMC Pharmacology and Toxicology 15.1 (2014): 1-8.
- Kesarwani, Kritika, and Rajiv Gupta. “Bioavailability enhancers of herbal origin: An overview.” Asian Pacific journal of tropical biomedicine 3.4 (2013): 253-266.
- Izgelov, Dvora, Abraham J. Domb, and Amnon Hoffman. “The effect of piperine on oral absorption of cannabidiol following acute vs. chronic administration.” European Journal of Pharmaceutical Sciences 148 (2020): 105313.
- Nakano, Yukako, et al. “Development of a novel nanoemulsion formulation to improve intestinal absorption of cannabidiol.” Medical Cannabis and Cannabinoids 2.1 (2019): 35-42.
- Atsmon, Jacob, et al. “PTL401, a new formulation based on pro-nano dispersion technology, improves oral cannabinoids bioavailability in healthy volunteers.” Journal of Pharmaceutical Sciences 107.5 (2018): 1423-1429.
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Gleb is a freelance writer from Vancouver, Canada specializing in CBD and cannabis. He’s read thousands of studies on CBD and other supplements, helping him translate complex science into plain language. Gleb has tried and reviewed dozens of CBD brands and products, written third-party testing reports, and knows the CBD industry inside and out. When not writing, he likes to kickbox, travel, and tell everyone how awesome intermittent fasting is.