CBD and Bioavailability

Times are exciting in the world of CBD right now. As an emerging therapy, research is well underway, looking into its potential health benefits. Meanwhile, it seems like a new, innovative CBD product gets introduced daily, from the latest CBD cream to chewing gum and CBD Gummy Bears.

Researchers are still exploring how CBD can relieve certain health conditions, and how much CBD is required to be effective. Beyond how much, there’s also the question of simply how. Is there a “best” way to take CBD?

The conversation about the “best” way to take CBD almost always touches on the topic of bioavailability. But what is bioavailability, and how does it affect your experience with CBD oil? We explore below. 

What does bioavailability mean?

Bioavailability refers to how much, and at what rate, something gets absorbed by your bloodstream. It’s important to understand the bioavailability of a substance because it helps you determine how much you need to take—and in what form—to ensure a proper dose actually ends up in your system. Otherwise, you may not feel the desired effects.

What is the bioavailability of CBD oil?

The bioavailability of CBD oil largely depends on the method of administration you use to administer it—in other words, how you consume the CBD. There are many ways to take CBD, from gummies and edibles to Softgels and topical products. Each of these methods has a different bioavailability.

CBD sublingual bioavailability

When administered sublingually (via drops held beneath the tongue), CBD oil has a sublingual bioavailability of 13% to 19%, with some studies putting it as high as 35%. Holding the CBD beneath your tongue allows it to be absorbed by your sublingual gland, through which it can enter the bloodstream and begin working its effects. While not quite as expedient as the inhalation method, sublingual administration of CBD still produces effects fairly quickly, within 20 minutes or so.

Of course, the trick here is to hold the CBD in the appropriate place (beneath the tongue) for an appropriate amount of time (30 to 60 seconds). If you swallow too soon, or apply the drops above your tongue and swallow quickly, you may as well be taking the CBD orally—which, as we’ll review in the next section, offers significantly lower bioavailability.

CBD oral bioavailability

Oral ingestion is popular because it’s a method people are already familiar with, from eating food, drinking beverages, and swallowing daily vitamin. Unfortunately, while oral ingestion may be common, it’s also the least effective method for taking CBD. The oral bioavailability of CBD is between 10% to 20%, although some studies have found it to be as low as 6%.

Why is CBD’s oral bioavailability so low? When you consume CBD orally, it must pass through your digestive system first, before it ever reaches your bloodstream. This process is not a quick one—taking up to 2 hours for some people—and during it, some of the CBD gets lost to the liver and digestive tract. As a result, you’ll have to wait longer for the CBD to provide relief, and the relief it does provide may not be as effective (since so much was lost during the journey).

CBD topical bioavailability

With all three of the above methods, you consumed the CBD through your mouth. There is one alternate way to take CBD—topically through the skin. With this method, CBD engages primarily with the endocannabinoid receptors located in your peripheral nervous system—so, it’s best for providing targeted pain relief in a particular area, such as arthritic joints or sore muscles. 

Because the CBD only interacts with local receptors in your skin, though, it won’t enter the bloodstream. As a result, topical administration will be ineffective for relieving conditions which require the CBD to bind to cannabinoid receptors in the brain and central nervous system, such as anxiety, epilepsy, or PTSD.

As with sublingual administration, topical administration requires the user to be aware of the correct method of application in order to experience the maximum benefits. While you do have pores in your skin, generally the skin is not very porous. It’s built to be a barrier that protects our internal organs from the outside world, after all. In order to bypass this protection, you need to apply CBD topicals liberally and vigorously into the targeted area, in order to ensure the CBD actually gets absorbed. 

The bioavailability of topical CBD hasn’t been quantified, although it’s expected to be low. Even so, multiple studies, including this one using purified CBD cream to treat MS-related limb paralysis, have found topical CBD to be effective at providing pain relief.

Can you increase the bioavailability of CBD?

You can’t really increase the bioavailability of CBD. What you can do, however, is optimize your method of administration to ensure you receive your ideal dose of CBD.

Keep in mind that all of the bioavailabilities listed above were achieved by expert researchers trained in administering the kind of hyper-precise doses required in scientific study. Your experience administering CBD to yourself may vary. But, you can still use these as a guide.

When taking CBD products at home, try multiplying the bioavailability rate by the amount of CBD in a serving size. The result of this calculation is closer to the “true” dose you’ll receive. Once you know the “true” dose, you can adjust your serving size accordingly. For example:

• A 1500mg tincture, where a full 1ml dropper provides a serving size of 50mg of CBD, may actually deliver 6mg to 17.5mg of CBD.

If you’re using CBD topicals, remember that their bioavailability is quite low, so you may have to experiment to find an effective dose. By their nature, dosing with CBD topicals is imprecise. Also be aware that you may require a higher-dose product than you expect, simply because it’s harder for the CBD to break through the skin.