Bioavailability

Bioavailability describes how much of an absorbed substance actually reaches the bloodstream and can take effect. It is a key reason why the same amount can have such different effects when administered by various methods.

What Bioavailability Means

Not everything that is absorbed actually reaches the bloodstream. Some of it is lost along the way – how much depends on the route of administration. High bioavailability means a large proportion is utilized; low bioavailability means a lot is "lost." This explains why methods cannot simply be compared 1:1.

Differences by Method

When absorbed through the lungs (smoking and vaping), bioavailability is comparatively high because the active ingredients enter the blood directly. With edibles, it is usually lower: on the way through the stomach, intestines, and liver, some of it is converted before reaching the bloodstream – this is known as the first-pass effect. With sublingually administered tinctures, it often lies in between.

Frequently Asked Questions About Bioavailability

Why is the word important?

Because it explains why the same amount has different effects depending on the method – some of it is lost depending on the route.

What is the first-pass effect?

The conversion of some active ingredients in the liver before they reach the bloodstream. It reduces the bioavailability of oral administration.

Which method has the highest bioavailability?

Generally, absorption through the lungs, because the active ingredients reach the blood quite directly there.