 Serum concentration of CoQ10 in fed condition is higher than in fasting conditions.Data on the metabolism of CoQ10 in animals and humans are limited.A study with 14C-labeled CoQ10 in rats showed most of the radioactivity in the liver two hours after oral administration when the peak plasma radioactivity was observed, but CoQ9 (with only 9 isoprenyl units) is the predominant form of coenzyme Q in rats.