Bioavailability = ACTUAL concentration of a nutrient IN THE BLOOD after ingestion. This is NOT as common an occurence as one would expect from supplements - especially as regards CoQ10!

This high molecular weight nutrient has a VERY large particle size that makes for difficult if not impossible absorption into the body. CoQ10 is mostly available in a powder or powder + oil formulation - then there is QGel Brand CoQ10 . Because it has been reduced to a submicron particle size, using a Patented Process, it has been shown, in study after study since 1998, to be 200-300% better absorbed than any other CoQ10 on the market.
(The Charts below show the results of the first Bioavailability study on QGel Co10 titled "Relative bioavailability of coenzyme Q10 formulations in human subjects"
Int J Vitam Nutr Res 1998;68(2):109-13)

And since you know how expensive CoQ10 supplements can be, you'll be happy to know that QGel brand doesn't cost any more than the less bioavailable ones and against some brands is even less expensive! You want to make sure that what you take is actually doing you some good! Ask questions and look for the proof!