How Cannabis Is Absorbed by the Human Body

As you may know, there are several ways to consume cannabis, such as inhalation, oral ingestion, through the mucous membranes of the mouth, and through the skin. However, the compounds that cause a high only take effect once they enter your bloodstream. This means that depending on how you consume cannabis, the effects may be stronger or take longer to feel. Read on if you’re interested in learning the differences between various methods of cannabis consumption and how cannabinoids are absorbed.

1. Vascular and Extravascular Absorption

For cannabinoids to start working in your body, they must enter the bloodstream. There are several ways THC and CBD can reach your circulatory system:

• Intravenous administration
• Extravascular absorption

Intravenous consumption refers to compounds being injected directly into the veins. This method is used only in scientific research to deliver precise doses, and we do not recommend this method at all. Extravascular consumption refers to any method outside the veins, such as smoking, vaping, eating edibles, or using topical creams—these are the most common methods used by cannabis consumers.

All methods, whether intravenous or extravascular, have their pros and cons. It’s important to know more about each to understand their effectiveness and to consume cannabis safely. For example, THC is almost fully absorbed within minutes after smoking a joint, while eating a cannabis edible may take an hour or more to feel the effects.

2. Group and Individual Variability

Group Variability

Group variability refers to differences in effects between people, meaning the same dose of the same product or substance may work for you but could be toxic or have no effect on someone else. Individual variability affects not only the effect but also the efficacy, safety, and tolerability of a particular substance.

• Age: As you age, your body changes, including your brain. Studies have shown that, for example, the volume and thickness of white matter in the frontal lobe change with age, which can alter how certain substances work.
• Sex: Recent research has found gender differences in the effects you may experience when consuming cannabis. Sex hormones play a key role, as do differences in muscle mass and fat distribution between women and men.
• Body Mass: Your weight also plays an important role in individual variability, as cannabis can affect you differently depending on your weight and the ratio of muscle to fat tissue.
• Medical Conditions: Illnesses affect individual variability because some diseases can impact the blood, brain, lungs, or any other organ involved in how cannabis is absorbed.

Individual Variability

Individual variability refers to the different effects the same person may experience when taking the same dose of the same substance. This happens because the same substance may not have the same effect depending on several factors.

• Consuming Cannabis with Food: Eating before or after consuming cannabis can affect the effects you feel. For example, eating after smoking may neutralize some effects. The amount of sugar and fat in your food can also influence individual variability.
• Mood: Cannabis amplifies your mental state. If you’re happy and consume cannabis, you may feel even happier or have no side effects. But if you’re sad, you may feel even sadder and have a negative experience.
• Time of Day: The time of day also affects the effects you feel. Consuming cannabis in the morning may make you feel more energetic compared to using it at night when you’re tired and want to sleep.
• Exercise: Physical activity can influence the effects you feel after consuming cannabis because exercise helps your cardiovascular system work more efficiently, which may allow cannabinoids to reach their receptors faster.

Group and individual variability may not seem significant, but they are crucial for understanding why effects vary from person to person. The effects can also vary depending on the method of administration (intravenous or extravascular), as well as individual and group variability. Additionally, the way you consume cannabis—such as smoking a joint or eating an edible—affects how cannabinoids are absorbed and how the effects may differ.

3. Inhalation Absorption

Inhalation absorption refers to absorption through the lungs. When inhaled, cannabis compounds like THC and CBD can be detected in the blood within the first two minutes, and effects are usually felt within the first 10 minutes. There are two main forms of this type of absorption: smoking and vaping.

• Smoking: Smoking is the most common method of cannabis consumption and provides a very fast effect due to the rapid delivery of cannabis compounds from the lungs to cannabinoid receptors. The bioavailability of cannabinoids after smoking is estimated between 2% and 56%, averaging around 30%, but can vary depending on individual or group variability, as well as the volume, duration, and intervals between puffs.
• Vaping: With vaporization, cannabinoids are absorbed just like with smoking: they enter your bloodstream through the lungs. The bioavailability range is similar to smoking, but usually higher, averaging around 35–50%.

4. Oral Route

This method refers to consuming edibles or any type of oral ingestion where the product is swallowed, enters the digestive system, and is then absorbed in the small intestine. Once in the intestine, the compounds go to the liver and then enter the bloodstream. Because absorption takes longer—as the food must travel from the mouth to the small intestine—it takes much longer to feel the effects compared to inhalation: it takes about 30–60 minutes to be detected in the blood and up to two hours to feel the effects.

Additionally, edibles provide a much stronger effect because the liver not only converts THC into Δ9-THC but also into 11-OH-THC, which is a much more potent cannabinoid that binds more easily to cannabinoid receptors.

Unlike other methods, the bioavailability of cannabinoids with oral ingestion is about 10–20%, meaning that out of all the cannabinoids in a cannabis cookie, your body absorbs only about 15% on average.

5. Mucosal and Sublingual Absorption

Mucosal absorption refers to cannabis products that are absorbed under the tongue or through areas of the mouth’s mucous membrane, such as the gums and the inside of the cheeks. The strength, duration, and effect will differ slightly when consuming cannabinoids through the mucous membrane. Absorption occurs within minutes or even seconds after use, unlike edibles, which can take hours. However, despite the fast-acting effect, these methods have a bioavailability that can range from 3% to 19%, averaging about 6%, which is quite low compared to other methods.

6. Transdermal and Topical Absorption

Absorption of cannabinoids through the skin can occur in two ways, both technically providing absorption through the skin but working a bit differently. These two methods are transdermal absorption and topical absorption.

• Transdermal Absorption: The transdermal method is a simpler way to use cannabis for those who cannot (or do not want to) smoke or eat cannabis. Because cannabinoids penetrate the skin, they can enter the bloodstream without being metabolized (processed in any organ), allowing you to feel the effects much faster—usually in less than 10 minutes. The downside is that cannabinoids are lipophilic, meaning they dissolve much faster in fats, so unless an absorption enhancer is used, the bioavailability may be only 5%. With an enhancer, voltage pulses, or ultrasound, it can range from 34–46%.
• Topical Absorption: Topical absorption works similarly to transdermal absorption, but with this method, cannabinoids do not penetrate deeply and cannot enter your bloodstream, so they have a low bioavailability, usually averaging about 5–15%. This method is most often used to treat symptoms in a specific part of your body, as cannabinoids do not reach layers below your skin, meaning they will only bind to cannabinoid receptors around the area where you applied the topical product.

Now that you know more about the different methods of administration and the bioavailability of cannabinoids, you can try different methods and better adjust your cannabis consumption depending on your needs to ensure the best effect and find what works best for you.