You’ve probably heard this term before, especially if you are an athlete or person who puts careful consideration into their diet and supplementation. But if you really only know it in context, or have not truly investigated what it is and why it’s important, this is your Cliffs Notes overview.


Bioavailability is a faction of absorption, so let’s start there. Absorption is the movement of a drug into the bloodstream from ingestion. Different nutrients have different rates of absorption, and they also consequently vary in bioavailability. Bioavailability is both how quickly something is absorbed into the bloodstream AND how efficiently your body can use it. If you take supplements and want them to work, bioavailability is a big deal. You need to know that the vitamins and nutrients you are ingesting will be actually used. Some nutrients compete for absorption or block absorption of other nutrients, so timing when you take your supplements is also key. 


There are multiple ways for nutrients, vitamins and minerals to be absorbed through the bloodstream and dispersed to the systems. MCT oil, for example, crosses the blood-brain barrier rapidly and powers the brain within minutes.

Other supplement ingredients need to be broken down, digested or metabolized before they can go to work. Collagen protein, for example, is first broken down into amino acids your body then rebuilds into the collagen and proteins it needs. This is why you should choose hydrolyzed proteins, they’re already broken down for easier absorption and improved bioavailability.

Further, it is important to know if any ingredients in the supplements you take are fat soluble. These should be ingested with a fatty food source to improve absorption. Not only are they stored in the fat in your body, but they team up with fats to permeate the intestinal wall to then be absorbed. According to a study from the Linus Pauling Institute at the University of Oregon, the blood indicators of people who took a vitamin E supplement while eating a bowl of cereal showed a significant increase in vitamin E, while those who took the supplement with water showed almost no boost in vitamin E. Vitamin D is another best absorbed when taken with about 11 grams of fat.


If a supplement doesn’t get into your bloodstream and to the right place, then why take it? There are so many supplements out there that capitalize on the fact that people just don’t know the determinants of a quality, bioavailable supplement, that a lot sneaks through and costs consumers a lot of money for very minimal value.

Take coconut oil, for example. We’re super into coconut oil right now, right? It’s a great source of MCT oil, right? Not really. It is a source of MCT, but not a good one. You’d have to eat spoonfuls of coconut oil to get a good amount of MCT, so the miniscule amount you’re whipping into your bulletproof coffee or half-and-halfing with your butter on toast likely isn’t giving you the benefits you think. Good marketing does not improve bioavailability.

Taking a supplement with food can decrease bioavailability. Oh, and taking a supplement without food can decrease bioavailability. Read the directions.

Does your fish oil taste like lemons, berries or anything else that isn’t … fish? It’s probably full of fillers and artificial flavoring that, sure, makes the supplement more palatable. But are you taking fish oil for the taste? Or for the health benefits? Typically, the two don’t go hand-in-hand and absorption/bioavailability of a nutrient can only be so high if you’re only actually getting so much of the nutrient in your supplement. Use common sense.

Basically, you want to choose supplements in their purest form with the fewest fillers for the highest bioavailability. Read your ingredient labels.

Some supplements actually have ingredients that can compete with others for absorption. A good way to make sure this isn’t happening is by looking for chelated minerals (key-late). Chelated minerals are minerals bound to a chelating agent, typically an amino acid, to improve absorption. Know what to look for.

In sum, bioavailability is important and drastically underconsidered when it comes to many supplementation decisions. Important things to remember regarding bioavailability are purity of ingredient, interactions it may have with other supplements, administration recommendations and product labels. Proprietary blends are a huge red flag. Always take as directed, and sometimes it takes a little more effort on your part such as knowing what minerals are fat soluble and how to best consume them.

Get the most out of your supplements and don’t waste your time or money on things that don’t deliver!


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