CBD Bioavailability And Placing CBD Under Tongue

CBD Bioavailability And Placing CBD Under Tongue
With so many ways to take CBD nowadays, it’s no wonder that many consumers feel a bit lost when deciding which method of consumption suits them best. The issue of CBD bioavailability—how much CBD reaches the bloodstream—further complicates matters.

Consumers who wish to try CBD must first determine the right CBD dosage—how much to take in order to experience the desired effect. This depends on CBD bioavailability, which, in turn, depends on various factors, such as the method of consumption. For example, placing CBD under tongue increases CBD bioavailability, while eating decreases it. Other factors come into play, too, including the quantity taken and even the general health condition of the person.

When deciding the best way to consume CBD, it’s important to understand how bioavailability works and how it affects people’s consumption of CBD.

What is CBD bioavailability?

Bioavailability is the rate at which the body absorbs a substance into the bloodstream.

Bioavailability is not limited to CBD. It refers to all substances, drugs, and medication. When establishing a drug’s dosage, for example, doctors have to evaluate its pharmacokinetics—what happens to the drug after it enters the body. Part of that is calculating the drug’s bioavailability: how much of the dosage reaches the bloodstream.

To measure that, they need to know how the drug’s various compounds are processed by the body, including the digestive tract and the liver.

For example, when a patient needs to take 10mg of an active substance and this substance has a 10% bioavailability, then the pharmaceutical company will create a medicine with an active substance content of 100mg per dose. This is because nine-tenths of it will be expelled without ever reaching the bloodstream. So, the medicine must have enough active substance to ensure that the patient’s body takes the amount it actually needs.

What are the various CBD consumption methods?

There are many ways of consuming CBD.

In the case of CBD, CBD bioavailability determines how much CBD a consumer needs to take and what form is the best.

There are many CBD products hitting the shelves. However, no matter the brand or product, there are just four main ways of consuming CBD, listed here in decreasing order of CBD bioavailability:

  • Smoking or vaping CBD. This offers the highest CBD bioavailability.
  • Sublingual consumption. Placing CBD under the tongue is different from eating it, as CBD is directly absorbed by the sublingual glands and enters the bloodstream without going through the stomach, gut, and liver.
  • Ingesting CBD. For example, edibles, gummies, and CBD oil are all ingested.  
  • Topical application. CBD creams work this way.

These four different ways of consumption differ wildly in the way the body takes in the CBD. Correspondingly, they offer CBD bioavailability that ranges from 5% to over 50%.

Vaping CBD

When vaping, the CBD enters the lungs immediately and binds to the endocannabinoid receptors through the lung capillaries.

Bypassing the digestive system lets CBD enter the bloodstream almost immediately. The effects are felt remarkably fast, usually within the first five minutes of vaping.

Unsurprisingly, vaping is the most bioavailable method of taking CBD: its bioavailability ranges from 34% to 56%. This means that vaping 15mg of CBD lets you feel the effect of between 5 and 8mg of CBD.

CBD under tongue

CBD tinctures are a way of consuming CBD without ingesting it. Consumers place a few drops of CBD under tongue and hold it there for 30 to 60 minutes before ingesting it.

Our tongue has capillaries in the bottom part. Substances are absorbed by the sublingual glands directly into the bloodstream.

As a result, feeling CBD’s effects takes as little as 15 minutes. Placing CBD under tongue offers a relatively high CBD bioavailability of 13% to 19%.

Sublingual use combines a higher bioavailability than oral consumption with ease of use, as you don’t need to carry the vape pens required for CBD vaping.

Ingesting CBD

CBD edibles, like gummy bears will take a long time to have an effect on you, becuase they go throught the human

When eating CBD oil, edibles, gummies, and other edible forms of CBD, you consume it orally. CBD then needs to go through the digestive tract before entering the bloodstream.

The human digestive system is designed to break down compounds through enzymes and digestive acids. What remains is metabolized by the liver before entering the bloodstream. That is why it can take up to two hours for CBD’s effects to be felt when consumed orally.

With so much CBD lost during the digestion phase, it is estimated that oral consumption of CBD offers a bioavailability of 10% to 20%, with most studies agreeing on the lower end. Therefore, when taking 15mg of CBD, your body will ultimately experience the effects of up to 3mg of CBD at most.

Topical use of CBD

CBD topical creams are specifically meant to help with skin inflammation such as acne, sore joints, and painful muscles. They’re not particularly helpful in other situations, as too little CBD will reach the endocannabinoid system to have any effect.

Topical creams offer the lowest bioavailability because the human skin is a formidable barrier to intruders. Topical CBD creams need to bypass 7 different layers of skin before entering the bloodstream, therefore losing a lot of the potency. It is estimated that the bioavailability of topical creams is usually under 5%.

That is not to say that CBD topical creams are useless. Evaluating the real bioavailability of topical CBD creams is particularly hard. The initial quantity used is rarely clearly defined or monitored. Most topical cream directions mention rubbing “a little cream” or “a small amount” on your skin, which are not precise quantities.

When applied in a measurable way, CBD creams can be effective. For example, a 2018 study showed promising results about the use of CBD topical creams and transdermal patches.

What do studies say about CBD bioavailability?

Several studies have been made and the results in all of them are very promising.

An increasing amount of research is directed towards understanding CBD and how it works. A 2018 pharmacokinetic study studying CBD bioavailability showed how the half-life of cannabidiol—i.e. the time for CBD to be reduced to half of its initial value in the body—ranged from a little over an hour to five days, depending on the circumstances!

  • CBD’s half-life ranged from 1.4 to 10.9 hours when applied in the form of oromucosal spray—i.e. sprayed under the tongue.
  • It was 24 hours when administered intravenously. Of course, this method of CBD consumption is only available in hospitals.
  • CBD’s half-life was 31 hours after smoking.
  • It was 2 to 5 days after chronic oral administration.

Can you increase the bioavailability of CBD?

The simplest way to increase CBD bioavailability in our body is to change the means of administration.

However, CBD bioavailability also depends on many variables, including weight, general health condition, and even genetics. For example, a healthy liver will metabolize more CBD than an impaired one. Therefore, a person suffering from liver problems will have more CBD in their system for a longer period than a person with a healthy liver, even if they consume the exact same quantity.

This is why there are no precise CBD bioavailability measurements for each method of consumption.


The most common way to bypass the bioavailability issue is for consumers to increase their initial dosage.

A higher dosage means that a higher quantity of CBD will enter the bloodstream even at a low CBD bioavailability.

Thankfully, several studies have shown that CBD is safe even in large quantities, and overdosing is almost impossible. The World Health Organization has issued a report stating that CBD is generally well-tolerated and with a good safety profile, agreeing with an earlier 2011 study.

Nevertheless, there is a threshold beyond which the body cannot absorb CBD—the so-called ceiling effect. Past a certain point, the tissues become saturated and cannot absorb any extra CBD excreted from the body.

Taking CBD with food

Just like topical creams, CBD when taking in certain ways will have very different results.

CBD is lipophilic, meaning that it dissolves in fats and oils rather than water. The human stomach is water-based. Therefore, an easy way to improve CBD bioavailability when ingesting it is to take CBD with food. This can improve CBD bioavailability by 3 to 5 times.

To maximize bioavailability, CBD should be taken with fatty foods such as avocado or healthy oils to make it easier for the body to absorb it. Food slows down the breakdown of CBD and allows more of it to linger in the body.

Frequency of use

The more CBD people consume over a long period of time, the more it stays in their body. Taking small but consistent doses of CBD could keep its levels in the body constant.

Since CBD is not addictive, its frequent but controlled use could increase its bioavailability in the body and prolong its possible effects.

Why CBD bioavailability matters

 CBD bioavailability matters because consumers need to determine the right CBD dosage. Taking too little may have no effect. Taking too much may cause some unwanted CBD-related side-effects such as drowsiness and nausea. That’s why consumers are strongly advised to consult with their GP to get proper medical and scientific advice before trying CBD. CBD can interact with medication and exacerbate existing medical problems.

Depending on the method of consumption, CBD bioavailability varies. Vaping is the most bioavailable method, followed by placing a few drops of CBD under tongue, oral consumption, and, lastly, topical creams.

To maximize CBD bioavailability, consumers can increase the dosage or take CBD with food to increase the final amount that enters their bloodstream.

Choosing the right brand and product can also make a big difference in CBD bioavailability. For example, emulsified CBD is water-soluble and readily absorbed by the body compared to CBD oil.


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