You could take the highest-quality herb on the planet and still barely notice a thing. Often times, the reason comes down to how much of it your body was able to absorb and use. Welcome to the world of bioavailability, the most crucial step of digestion that we often take for granted.
You aren’t what you eat, you’re what you absorb!
There’s a popular theory that human brains got way bigger when we started cooking our food. There’s still some debate on if that’s true, but it remains a solid argument because of bioavailability.
In short, bioavailability is the percentage of an ingredient that actually makes it into your bloodstream, where your cells can put it to work. Often, we assume that if we eat something, we use it all, but this simply isn’t true.
Eating isn't the same as absorbing. A lot of what we consume, especially plant compounds, gets broken down, ignored, or flushed out before it ever reaches circulation. Think of it like getting mail: a package isn’t useful to you until you’ve opened the box and retrieved the item inside.
A Quick Trip through Digestion
To understand how the body absorbs nutrients, it helps to follow the basic path nutrients have to take.
First, the brain – we often forget, but we ALL know the feeling of thinking about food and immediately having our mouths start to water. Prepping our body for food is the first step in digestion.
Then, the mouth and the stomach begin breaking food down using enzymes and stomach acid to dissolve each piece into smaller bits.
Next, the small intestine is where most absorption actually happens. Nutrients have to cross the intestinal lining to enter the bloodstream, which is where a lot of potential gets lost. Some molecules are too large, water-resistant, or fragile to make the crossing.
Finally, the liver filters everything absorbed from the gut before it reaches the rest of the body (a process called first-pass metabolism). We love the liver because for this protective step, though it can also break down helpful compounds before they have a chance to do anything.
Every one of these steps is like a checkpoint and something can be lost or added at each one. That's why two people can take the exact same supplement and experience it differently. Factors like digestive and liver health, your gut microbiome, other food in your stomach at the time, and even age can all influence how much gets absorbed.
What makes an ingredient easier to absorb
The food or supplement itself matters too, and three factors play a big part:
- Solubility: Some compounds dissolve easily in water and others only in fat or alcohol. Anything that can't dissolve in your digestive fluids usually passes right through, like insoluble fiber (which is exactly what fiber is supposed to do).
- Molecule size: Larger, more complex molecules often can't pass through the intestinal wall, no matter how beneficial they are in a lab setting.
- Timing: Taking something on an empty stomach versus with food can speed up or slow down absorption, depending on the compound.
This is part of why a supplement that shows powerful results in a lab doesn't always translate the same way once it's actually inside a person. The compound might be effective in theory, but if it can't survive digestion and cross into circulation, that potential never gets realized. It’s also why not everything you eat turns into nutrients for your body.
How to choose your herbs
This is where bioavailability (and this blog) becomes less of a science lesson and more of a helpful guide. Not all forms of an herb are absorbed equally, and the extraction method plays a major role.
Raw, unprocessed herb powder tends to have the lowest bioavailability (meaning it’s the hardest for your body to absorb). Many beneficial plant compounds are locked inside tough plant cell walls and need to be broken down before your body can access them.
Traditionally, such as in Chinese Medicine, long water decoctions (where herbs simmer for hours) are used. This is especially important for hard resinous compounds like chitin, found in Reishi, because our bodies have a really hard time breaking it down. This means that if you eat raw Reishi powder, you likely aren’t unlocking all the beneficial compounds, but instead flushing it down the toilet.
Extracts, particularly those using both water and alcohol, commonly known as double extracts, tend to offer better bioavailability because the extraction process has already done some of that work for you. Water pulls out compounds like polysaccharides, while alcohol draws out others, like triterpenoids, that water can't reach on its own. The result is a more concentrated, more accessible form of the herb. The result? A form your body can easily use.
Liquid tinctures or powdered extracts are even more helpful. Since they skip some of the breakdown that solid capsules or tablets require, they can be absorbed more quickly.
Sourcing & Formulation Matter Too!
An herb grown in poor soil, harvested at the wrong time, or processed with too much heat can lose potency before it even reaches an extraction tank, and even the best extraction can’t make up for compounds that were never there.
There's also a growing body of research into natural "bioavailability enhancers" or compounds that help other compounds absorb better when taken together. We’ve all heard about adding black pepper to Turmeric. But, why? Well, its active compound, piperine, helps the body access and use Turmeric's beneficial compounds more effectively. This is part of why thoughtful formulation matters too! Skilled herbalists are taught about these compounds to help make herbs more easily accessible to you.
None of this is meant to overwhelm you. It's meant to help you ask better questions when you're choosing a supplement. Look past the ingredient list alone: two products can list the same herb and deliver very different results depending on extraction method and sourcing quality.
Extracts generally outperform raw powders, since a properly made extract has usually already done the work your digestive system would otherwise have to do. And more concentrated isn't always better! A highly potent extract your body can't absorb well is less useful than a well-formulated one your body can actually recognize.
Why we care
Bioavailability is the difference between what’s physical versus what’s functional. A food or an herb might have a nutrient, but if your body can’t unlock it, then it’s of no use to you.
This is why we care so much about sourcing and extraction methods behind the scenes. We care about making sure that we’re providing you with something that’s actually helpful for you!