What is Bioavailability?
Bioavailability is a pharmacological term for the proportion of a drug or supplement that enters circulation and is able to have an active effect. A bioavailability of 100% means everything you consume reaches your bloodstream. A bioavailability of 10% means only 10% does — the rest is wasted.
It's one of the most important factors in determining whether any supplement actually works, and it's the factor that the CBD industry has largely ignored.
CBD Oil Bioavailability: The Numbers
Multiple peer-reviewed studies have measured the bioavailability of oral CBD oil, and the results are consistently disappointing:
The reason oral bioavailability is so low comes down to the first-pass effect. When you swallow CBD oil, it passes through your digestive system and is metabolised by the liver before it reaches your bloodstream. A significant portion is broken down and excreted before it ever has a chance to work.
Why Fat-Soluble Compounds Are Poorly Absorbed
CBD is a fat-soluble (lipophilic) compound. Fat-soluble substances don't dissolve in water — and your digestive system, bloodstream, and cells are largely water-based.
When you take CBD oil, your body has to work hard to absorb it. It needs bile acids to emulsify the oil into tiny droplets, which then pass through the gut wall via specialised transport proteins. It's a slow, inefficient process, and a lot gets lost along the way.
This is why eating CBD oil with a fatty meal improves absorption — the additional dietary fat stimulates more bile acid production, improving emulsification. But even with this trick, you're still only getting a fraction of what you paid for.
The Nano-Emulsification Solution
Water soluble CBD solves this problem by doing the emulsification work before you consume it. Using high-pressure homogenisation or ultrasonic processing, CBD is broken into nano-particles — droplets smaller than 100 nanometres.
At this size, the CBD particles can:
1. Mix fully with water — no separation, no oil layer
2. Pass directly through the gut wall — bypassing much of the first-pass metabolism
3. Enter the bloodstream rapidly — reaching peak plasma concentration significantly faster than oil
The result is bioavailability of up to 90%. You absorb more, faster, with a lower dose.
What This Means in Practice
If you're currently taking 50mg of CBD oil daily and experiencing limited effects, it's worth considering how much is actually reaching your system. At 13% average bioavailability, that's around 6.5mg of active CBD.
With water soluble CBD at 70% bioavailability, a 10mg dose would deliver 7mg — more than the 50mg oil dose, at a fifth of the quantity.
This has real implications for cost, consistency, and effectiveness.
The Importance of Purity
Bioavailability improvements only matter if you're starting with high-quality CBD. A 90% bioavailable product made from 97% pure isolate will deliver more impurities to your system than a 90% bioavailable product made from 99.9% pure isolate.
AquaCBD uses 99.9% pure Colorado-certified CBD isolate — the highest purity commercially available — combined with nano-emulsification technology for maximum bioavailability.
Join our waitlist and be first to experience the difference.