Supplement Bioavailability: Why Absorption Beats Dose

Bioavailability, Defined Plainly

Put simply, it's the fraction of a dose that gets into the bloodstream in an active form. When an ingredient is absorbed badly or broken down fast, much of the dose never gets to the tissues where it's meant to work. That's why the label amount doesn't tell the whole story.

Ingredients With Absorption Problems

• Resveratrol: It dissolves poorly in water, and the gut and liver metabolize it quickly, so oral bioavailability is low whichever brand you choose
• DIM: In crystalline form it's poorly absorbed, which is why most products rely on absorption-enhanced formulations
• Curcumin: On its own it's absorbed very poorly, and the body metabolizes or excretes most of an oral dose
• Fat-soluble vitamins (D3, K2): They need dietary fat to be absorbed

Ways to Improve Absorption

• BioPerine — a branded black pepper extract (piperine). In studies the supplier funded, it raised blood levels of certain specific nutrients. Most of the formulas it's added to haven't been tested with it
• AstraGin — a branded blend of astragalus and Panax notoginseng extracts. The absorption data behind it come from supplier-funded studies of other nutrients
• Phospholipid complexes — can improve absorption of some poorly soluble compounds, depending on the ingredient
• Liposomal delivery — compounds are wrapped in phospholipid spheres. For most liposomal supplements, better absorption hasn't been shown in people

Your questions, answered