What is CBD bioavailability and why does it matter?

In researching CBD, you may have come across the term bioavailability. It might sound like this is something for those involved in the science end of things, but its impact is relevant to even occasional users of CBD. If you want t get the most out of your CBD, here’s how knowing about bioavailability can help.

What does bioavailability mean?

Bioavailability refers to how much of a substance, such as medication, actually reaches the site where it can be effective. Although you might be taking a dropper of CBD oil that contains 1mg of CBD, some of this is lost as it is processed by your body.

If you think about medication that is given intravenously, all of this is going directly to your bloodstream, so it would have 100% bioavailability. For any other method of administration such as oral or topical, the compound needs to pass through other parts of the body, where it loses some of this bioavailability.

CBD bioavailability

Obviously, CBD should not be administered intravenously, so there is no method that will give you 100% bioavailability. But let’s look at some of the different ways you can use CBD and how they stack up.

Sublingual

It’s important to recognise the difference between taking something orally and sublingually. Taking something orally is by eating or drinking it, whereas sublingually only applies to something that is placed under the tongue.

CBD oils or tinctures are usually recommended for sublingual use. For maximum bioavailability, the drops should be held under the tongue, without moving the tongue or swallowing for around 30 seconds. This allows the CBD to enter the bloodstream via the sublingual gland, rather than going through your body’s digestive process.

When done correctly, sublingual CBD applications can have a bioavailability of up to 19%, though some studies say it may be as high as 35%. It’s also an efficient method of delivery, with effects felt in around 15-20 minutes.

Oral 

Gummies are the most popular way of taking CBD orally, but you may also find other edibles such as chocolate or cake pops. When you take CBD in this way, the compound goes first goes through your digestive system and the liver before eventually being absorbed into your bloodstream.

This process can take up to 2 hours before any effects are felt, and the bioavailability is around 10-20%.

With such low bioavailability, it may seem like oral administration is not the best option. But in fact, CBD edibles are very useful for the fact they have such a precise dose. Beginners to using CBD may also feel more comfortable with this option as it is more familiar.

Smoking or vaping

We know more about the bioavailability of smoking CBD, as this was the traditional way of using cannabis. It is not only a very effective method in terms of the time it takes to have an effect, but it also retains a higher percentage of CBD during the process.

As the smoke is inhaled it goes into the lungs, where it is absorbed into the bloodstream by the alveoli. This takes around 3 minutes and retains a bioavailability of around 31%. The downside to this is that some compounds produced during the burning process can damage the lungs.

While vaping is very similar to smoking, not enough research has been done to confirm the exact numbers, though some studies say it may be as high as 56%.

Intranasal

An intranasal application such as with a spray or vaporiser is not as common but can be a great option for those looking for a high bioavailability rate.

Just as with smoking, CBD that’s inhaled through the nose ends up in the lungs where it can enter the bloodstream. But additionally, some CBD is absorbed through the mucous membranes in the nose. The result is a bioavailability of 34-46%. 

Topical

Strictly speaking, topical application of CBD doesn’t have a bioavailability, as the compound doesn’t tend to make it to the bloodstream. However, this doesn’t mean it is not effective.

Topical CBD is used to interact with the endocannabinoid receptors in the skin, rather than in the brain or central nervous system. This is why topical applications such as creams and balms are used to treat localised pain, rather than to aid relaxation or treat insomnia.

Can you increase CBD bioavailability?

While the bioavailability is mostly determined by the chemical processes in the body, there area couple of things you can do to aid efficiency. When taking CBD orally, try having it with a fatty snack. CBD is oil soluble, and the fat from the food will help to break it down and make it more easily absorbed by the body.

When taking CBD sublingually, try to hold it under your tongue for the full 30 seconds. This gives it more chance of being absorbed directly into the bloodstream – as anything you swallow will end up going through your digestive process.

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