In our previous blog “Ubiquinol and Your Heart: The Cellular Story,” we discussed the role of Ubiquinol, the active antioxidant form of coenzyme Q10, in energy production and heart health. Given its critical role, it is important to understand its bioavailability and pharmacokinetics to aid in proper clinical use.
As you may know, coenzyme Q10 in its basic form is not highly absorbable in the body. But studies suggest that Ubiquinol has superior absorption and can replenish the normal CoQ10 plasma concentration. In a randomized, double-blind, crossover study, the bioavailability of Ubiquinol and coenzyme Q10 were compared using an acute intake of 100 mg in 10 healthy subjects with 2 weeks between treatments. Plasma concentrations were significantly higher for Ubiquinol compared to coenzyme Q10 at 6, 8, 12, 24, 48, and 72 hours post-intake (P<0.001) and the AUC for Ubiquinol 72 hours post-intake was 4.3-fold greater than for coenzyme Q10.1
This greater bioavailability was also shown for chronic intake. In a crossover, comparative study in 12 healthy subjects, uptake of Ubiquinol and coenzyme Q10 (200 mg/d) were compared after four weeks of supplementation. Ubiquinol was absorbed over two times as well as ubiquinone in direct comparison (P<0.005). When comparing final plasma concentrations, Ubiquinol was absorbed 1.7 times more than CoQ10 (4.3 µg/ml vs. 2.5 µg/mL), or 70% better.2 A possible mechanism for this is increased micellarization in the gut, because the reduced nature of Ubiquinol facilitates micelle formation, a necessary step in absorption in the small intestine.3
The amount of absorption will vary based on a person's age and state of health, but in every published comparative study that has been done, Ubiquinol has consistently been much better absorbed than coenzyme Q10 and replenishes the plasma concentration.1,2,4-8
Along with bioavailability, transportability in the blood to the sites of use is a key factor in efficacy. Ubiquinol is transported in the blood by attaching to lipid low density lipoprotein cholesterol (LDL cholesterol) particles. If coenzyme Q10 is ingested, the body quickly transforms it into Ubiquinol via an enzymatic reaction, making it the form that is most preferred by the body for transport in the blood.6 Some people cannot perform that transition very efficiently, and therefore receive very little benefit if they take coenzyme Q10 as opposed to Ubiquinol (look for a future blog on this topic!). However, in a healthy adult, more than 95% of the total coenzyme Q10 in the blood is in the Ubiquinol form.9-11 A major portion of CoQ10 in tissues is also in the reduced form as Ubiquinol.10
CoQ10 has a Tmax of 6.5 h and an elimination half-life of 33.19 h, meaning that once-a-day dosing is sufficient. Chronic administration produces a dose-dependent increase in plasma total Coenzyme Q10.12