What is Bioavailability?
Bioavailability is the share of a nutrient or compound that actually reaches your bloodstream in active form after you take it, as opposed to the amount printed on the label. Two products can list the same dose yet deliver very different amounts to your body.
Bioavailability is the gap between the dose you swallow and the dose you absorb, and the form of an ingredient is a big part of why that gap exists. It is the reason a chelated mineral can outperform a cheap salt, why elemental magnesium matters more than the total weight of the compound, and why a gentler form such as magnesium glycinate is often preferred over harsher options.
It matters most to anyone comparing supplements on how well they are absorbed rather than on headline dose alone. The catch is that bioavailability varies from person to person and shifts with food, timing and gut health, so a form that absorbs well on average may not for you. High absorption also counts for nothing if the underlying dose is too small to do anything in the first place.
If you want a magnesium chosen for how well it is absorbed, our Magnesium Glycinate uses a form selected for that reason.
Frequently asked questions
How is it different from the dose on the label?
The label dose is how much compound is in the product. Bioavailability is how much of that actually enters your bloodstream in a usable form, which is often a good deal less.
Who uses it, or when is it the right choice?
Anyone weighing two supplements should look at bioavailability, not just milligrams. It is the deciding factor when the same nutrient comes in several different forms.
When is it the WRONG choice?
Chasing the most bioavailable form is pointless if the dose is too low to matter, so it is the wrong first question for an under-dosed product. It also matters less for nutrients your body absorbs easily regardless of form.