Waste Not, Want Not: Understanding the Importance of Bioavailability and CBD

by PP Health Admin / Nov 16, 2021

Every drop counts when it comes to CBD. Whether you use it for its potential to promote relaxation or to help maintain your wellbeing, you want to make sure you get the most out of your CBD experience. However, not all CBD products are the same. From taking a daily CBD capsule to adding CBD drops to your morning coffee, there are a plethora of ways to use CBD, and each method has a different bioavailability level.

As with most things in life, people have their individual preferences and needs. While some opt for traditional CBD products, such as oils and balms, others prefer the fun side of things in the form of gummies, smoothies and other delicious edibles. This leaves us with an important question: how can we tell if it’s the right one for us and how much CBD should we take?

Knowing more about how and how much CBD is absorbed into the body can help you decide on the product that matches your style most. An essential term to understand when experimenting with your options and to determine the right dosage is bioavailability. Just the sound of it can be a little intimidating if you're fairly new to the industry; however, the concept is relatively simple so let's get straight into it!

CBD Bioavailability: What Happens When You Take CBD?

Formally known as Cannabidiol, CBD is a non-intoxicating cannabinoid found in many cannabis variants, including hemp. Hundreds of scientific studies suggest that CBD may have the potential to help support our overall health and wellbeing. Its non-psychotropic nature and impressive therapeutic profile make CBD a promising solution to a host of health problems, such as pain, stress, anxiety, and more.

In order to become potentially effective, CBD has to enter the body and reach the endocannabinoid system (ECS) through the bloodstream. The ECS is a regulatory network composed of endocannabinoids that interact with multiple sensory receptors all over the body. An important job of the ECS is to maintain a holistic balance within the body, a concept known as homeostasis.

Some experts believe that cannabinoids like CBD imitate the body’s natural endocannabinoids, allowing them to bind with several receptors and impact the ECS. Once CBD penetrates the body, it has to stay in the bloodstream for a substantial period, long enough to reach the specific areas it needs to be.

As mentioned earlier, CBD comes in different types and formulations that require unique delivery systems. These include oral, sublingual, intranasal, and topical administrations. Some of these methods may have higher potency and quicker absorption levels than their counterparts. It’s all down to the bioavailability rate of the product used in the process.

Bioavailability is the degree and rate at which a drug or substance is absorbed into the bloodstream and becomes available to its targeted biological destination(s), depending on how it has been consumed. When it comes to CBD, the bioavailability rate of a product determines how fast the active ingredients enter the bloodstream and how much of the solution is used by the body. The higher the bioavailability level, the more readily available it will be in the bloodstream.

The bioavailability rate of a particular CBD product largely depends on its delivery system. Intravenous administration, for example, presents the highest bioavailability level, among other consumption methods. This is likely because it involves injecting the product directly into the bloodstream through the veins, which provides up to 100% bioavailability. While it may deliver “all” of the active ingredients into the body, it’s not the most popular option available. The process requires medical training, and not everyone is a fan of needles, which makes it relatively inconvenient and unappealing.

In addition, CBD’s bioavailability may be influenced by several physiological factors, such as age, sex, metabolism and genetic makeup. Since everybody and every body is not the same, there is no universal measurement of CBD bioavailability that applies to everyone. For instance, two different users consuming the same product in the same dosage may experience different potential effects due to their individualities.

Let’s look at each delivery method for CBD and see what current studies tell us about their comparative advantages and disadvantages in terms of effectiveness and practicality.

Oral Consumption

Woman taking a CBD capsule.

Oral CBD consumption refers to any CBD-based products taken through the mouth. Some common products that require this method are CBD capsules, gummies, smoothies and other readily available beverages and edibles.

Oral consumption is one of the most popular ways to take CBD, and for good reasons. It’s easy, discreet and delicious! You can enjoy your CBD cookies all you want, and no one will ever notice that it’s CBD you’re eating! However, taking CBD orally may not be the best option when it comes to obtaining the optimal level of bioavailability.

The problem with cannabinoids is that they are made up of oil-based molecules, which does not mix well with water. Since our bodies are composed of 60% water, it can be challenging to dissolve, and more importantly, absorb such substances.

When a CBD capsule is ingested, the active ingredients in the product have to undergo extensive first-pass metabolism, which can take up to eight hours or longer. This means that you will have to wait longer to feel the potential results. During the first-pass effect, a large portion of the food or supplement you consume is filtered by the liver before reaching the bloodstream. This process significantly influences the bioavailability level of oral CBD products. Hence, experts suggest that the oral bioavailability of CBD may be very low, ranging between 13% to 19%.

Put another way, if you take a CBD capsule that contains 50 milligrams of CBD, only a maximum of 9.5 milligrams can make it to your bloodstream and the rest of your body. Nonetheless, it's possible to reap more of CBD's potential benefits by choosing a different mode of consumption. While oral consumption may not impress you that much given its low bioavailability index, the following method might do!

Sublingual Consumption

A woman placing CBD oil drops under the man's tongue.

Sublingual consumption is when you place a few drops of CBD oil under your tongue and securely hold them there for about 60 to 90 seconds before swallowing. This method provides a direct route to the bloodstream via the mucous membranes underneath the tongue.

Once an active ingredient is absorbed into these particular veins, it is administered directly into the bloodstream. That means that CBD doesn't have to go through the first-pass metabolism. The active substance may only be degraded by the enzymes found in the saliva, but that's nothing compared to the number of nutrients that might have been lost during the metabolic process. As a result, research shows that the sublingual bioavailability of CBD may be approximately up to 35%.

With a relatively higher bioavailability index, sublingual CBD products may offer a quicker onset of potential effects to the body. Just make sure to avoid swallowing the drops too soon or placing them mistakenly above your tongue. Otherwise, you may as well be taking your CBD oil orally and getting a lower bioavailability rate in return.

Intranasal Consumption

A man in glasses vaping CBD

Intranasal consumption of CBD has the second-highest bioavailability level, ranging from 34% to 46%. Some studies suggest that this method can range up to 56%, making it one of the most potent ways to consume CBD.

Intranasal consumption includes the use of vaporising devices, such as vape pens or e-cigarettes. Some people even use nebulisers to administer CBD in the form of mists inhaled into the lungs. Similarly, the goal of vape pens is to inhale CBD-infused vapour into the tiny membranes of the alveoli found in your lungs, which offer a straight route to the bloodstream.

This method allows CBD to bypass the metabolic phase in the digestive system, thereby offering a higher index of bioavailability and quicker onset of possible effects compared to most other methods. As a result, you may inhale a significant amount of CBD in every puff. With that being said, the potential efficiency of intranasal CBD consumption is central to multiple studies, as more clinical evidence is still needed to fully understand the long-term impacts of vaping on the lungs.

Topical Application

A woman holding cannabis leaves while applying CBD oil to her skin

Applying CBD to the skin is a common part of self-care rituals these days. There will never be a dull moment in the bathroom with such an exciting list of innovative CBD products for your skin, from lotions to serums and even bath bombs. Unfortunately, there's no scientific evidence to quantify the topical bioavailability of CBD. This owes to the fact that topical application does not require active ingredients to pass through the bloodstream.

Instead, topical CBD may directly engage with the cell receptors surrounding the peripheral nervous system (PNS). The PNS is mainly responsible for collecting signals from the skin, muscles and other sensory organs. In this light, the topical application of CBD might be beneficial for localised pains and other discomforts.

Alternatively, a newly-developed method called transdermal administration may allow CBD to enter the bloodstream through the skin. This approach requires a CBD-infused adhesive patch to be placed on the skin. However, the absorption rate of transdermal administration is relatively lower than the previous methods. This is due to the water-soluble layers of the skin, which act as a barrier to CBD absorption.

Other Factors that Affect CBD Bioavailability

CBD bioavailability is influenced by many internal and external factors, which are not limited to the way CBD is delivered into your system. While the consumption methods presented above are helpful indicators of the changes in CBD bioavailability, other localised factors can affect how active substances like CBD are absorbed into the bloodstream.

Fortunately, there are ways to control some of these factors so that you may use them to your advantage. Before we reveal the secrets to maximising the bioavailability of CBD, let us first hold a magnifying glass to each determinant below and see how it impacts CBD bioavailability.

Pre-existing Health Condition(s)

Your state of health plays a critical role in CBD absorption. Your liver, for example, is essential in eliminating active ingredients from the bloodstream and exporting them to various parts of the body where they are needed. Hence, an impaired liver function significantly affects the potency of oral CBD products and how long they remain in the system.

A recent study shows that individuals with moderate to severe liver failure are more likely to have a decreased level of CBD absorption and longer clearance times. The same goes for other health conditions. You may need to adjust your preferred CBD dosage or consumption method accordingly if you have any underlying health concerns. Most importantly, it’s best to consult your doctor before using CBD.

Full vs Empty Stomach

You might wonder why some medications or supplements like CBD are usually taken after every meal. That's because the presence or absence of food during CBD consumption may substantially impact its absorption and clearance rates.

A study conducted at the University of Minnesota suggests that CBD may be administered into the bloodstream more effectively when consumed with a high-fat meal than when fasted. This is reportedly due to the fat-soluble nature of CBD. When you take CBD alongside a healthy source of fats in your diet – such as fish, avocado, nuts or dairy products – CBD binds with all these dietary fats and dissolves into smaller fragments that are easier to absorb.

According to a separate study, high-fat foods are thought to help slow down the clearance rate of CBD, allowing the nutrients to stay in the system for an extended period. On the other hand, an empty stomach may influence the rate at which CBD is eliminated from the body.


Hemp undergoes a series of extraction procedures to convert cannabinoids into active compounds. Typical extraction methods include heating, which can reduce absorption efficiency. In short, heat largely affects the bioavailability level of some CBD products. In fact, research suggests that the bioavailability of unheated CBD extracts may be higher compared to their heat-treated counterparts.

How to Enhance CBD Bioavailability

We all wish to reap most of the potential benefits from CBD, regardless of our selected delivery method. The desire to do so often has us believe that the higher the bioavailability index, the better our CBD experience. However, there is no one-size-fits-all solution when it comes to increasing the bioavailability of CBD. There are, rather, ways to help boost our preferred CBD products and delivery methods to ensure our bodies receive a reasonable amount of CBD.

Here are some easy tips and tricks to possibly enhance the bioavailability of CBD:

Adjust Your Dosage Accordingly

When taking CBD for the first time, the general rule is to start with low doses and then gradually increase them over time. Adjusting to higher doses may help double the bioavailability of your preferred CBD product and way of administration.

To get your ideal CBD dosage, multiply the bioavailability rate of your elected method by the amount of CBD per serving. Suppose you’re using CBD oil sublingually, and it contains 50 milligrams of CBD in 1 full dropper. When you multiply the maximum bioavailability level of the sublingual method by your preferred CBD serving size, the equation will look like this: 50 mg x .35 = 17.5 milligrams of CBD.

According to the British Food Standards Agency (FSA), the maximum amount of CBD that healthy adults can consume per day is about 70 milligrams. You may wish to adjust your daily intake of CBD oil up to 4 drops if you want to increase its efficacy and bioavailability rates. However, it's essential to keep in mind that there are potency limits when it comes to CBD dosage. This means that taking higher doses of up to 800 milligrams per day won't likely change a thing. It's because your tissues become saturated when you consume large amounts of active compounds, making it hard for the bloodstream to absorb more CBD.

Consider Supplemental Ingredients

Oral CBD consumption may have the lowest rate of bioavailability, among other methods, but there are many ways to help you get the most out of this approach. The first hack is what we’ve mentioned earlier – combining CBD edibles with high-fat foods. In addition, scientists are now studying the composition of supplemental herbs like black pepper and how they might be used as an effective tool to improve the oral bioavailability of CBD.

Black pepper contains piperine, a chemical compound packed with absorption-boosting properties. Hence, it is proven to help enhance the bioavailability of curcumin, a lowly-bioavailable compound found in turmeric. Conclusive evidence supports that piperine may influence the transport proteins that enable curcumin to enter the bloodstream.

Terpenes are another interesting option if you're looking for supplemental herbs to combine with CBD. They are aromatic compounds that naturally occur within the hemp plant and are often used for fragrances and flavours of many self-care products. Terpenes come packed with essential fatty oils that are beneficial when it comes to amplifying the efficacy of CBD. When CBD is used with terpenes, it may offer an entourage effect. The concept of the entourage effect suggests that combining two or more compounds may provide better results, with one compound possibly strengthening the potential effects of another.

This leads you to the next important step. Not all CBD products have the same formula, so make sure to read the label carefully when looking for something with a potential entourage effect. CBD products come in different spectrums, including full-spectrum, broad-spectrum, and CBD-isolate. These categories will help determine the presence of CBD, terpenes and other necessary compounds in the product's formulation.

Full-spectrum CBD products contain CBD extracts and other essential cannabinoids and chemical compounds found in hemp. These include terpenes, fatty acids, and a fair amount of tetrahydrocannabinol (THC) – the primary psychoactive component of the cannabis plant. Broad-spectrum CBD products have an almost similar formula as the previous type, except for the THC part. Lastly, CBD isolates contain nothing but pure CBD extracts. As you examine the differences among these options, you might want to consider products with full-spectrum CBD formula if you’re after the entourage effect.

Use Ethanol

This trick usually applies to topical CBD products. The transdermal bioavailability of CBD is relatively low, more or less 3%. An effective workaround is applying ethanol to the affected area and drying it before placing the CBD patch. You may also opt for CBD patches that already contain ethanol. This ingredient may help increase the absorption rate of CBD by making the active substance more water-soluble.

The Bottom Line: Why Bioavailability Matters

Understanding how CBD bioavailability works not only helps you to maximise the use and efficacy of various CBD products, it also helps to spare yourself the potential disappointment of ineffectiveness or overspending on a product that is not suitable for you. Let’s try to calculate the cost of two different CBD options.

On one hand, lies a 100-mg CBD capsule that costs £50. The maximum bioavailability rate of oral CBD consumption is 19%, so around 19 milligrams of CBD may enter your bloodstream. This means that you are paying £2.6 for every milligram of CBD capsule. On the other hand, is a 100-mg CBD oil with the same price as a 100-mg CBD capsule. Since the maximum sublingual bioavailability of CBD is 35%, about 35 milligrams of CBD may be administered into your bloodstream. Each milligram of CBD oil will cost you £1.4, which is half the price of a CBD capsule per milligram.

All in all, the message is clear: when shopping for CBD, it pays to be aware of what your body will possibly gain from your product of choice. Some people may feel the optimal results from sublingual CBD consumption, while others may prefer a different mode. It doesn’t hurt to try all of those delivery methods until you find what works for your body. At the end of the day, trial and error is just an essential part of the CBD journey. You’ll never know what’s best for you if you never care to try anything at all.