Understanding Bioavailability in Supplements

Bioavailability—the proportion of a substance that enters circulation when introduced into the body—is perhaps the most crucial yet overlooked factor in supplementation. Two supplements containing identical amounts of a nutrient can have dramatically different effects based on their bioavailability ^[1].

What Determines Bioavailability?

Multiple factors influence how well your body can absorb and utilize a supplement:

Figure 1: Key factors affecting supplement bioavailability

Chemical Form

The chemical form of a nutrient significantly impacts its absorption. For instance, iron comes in two primary forms: heme (from animal sources) and non-heme (from plant sources and most supplements). Heme iron has a bioavailability of 15-35%, while non-heme iron's bioavailability ranges from just 2-20% ^[2].

Delivery System

The physical delivery system of a supplement can dramatically alter its effectiveness:

Figure 2: Comparison of different supplement delivery systems and their impact on bioavailability

Liposomal encapsulation—where nutrients are enclosed within tiny lipid spheres—can increase bioavailability by protecting compounds from digestive breakdown and facilitating direct cellular absorption. Studies show liposomal vitamin C achieves 135% higher blood concentration than standard oral forms ^[3].