The bioavailability of coenzyme Q10 (ubiquinone) formulated as an emulsion in a soft gelatin capsule (Ensorb(TM), NDS Pty Ltd, Sydney, Australia) was compared with a hard gelatin powder-filled capsule. The study design was a randomized cross-over trial with a 3-week wash-out period. The study population comprised 23 apparently healthy adults (12 men and 11 women), aged 20-43 years. Each participant took two 50 mg capsules, and blood samples were taken over a period of 36 h. The plasma concentration of coenzyme Q10 peaked between 3 and 4 h after administration of both preparations. The area under the curve (AUC) of Ensorb™ was 927% higher than that observed with the powder-filled capsule (P < 0.0001), suggesting that this emulsion preparation has a higher bioavailability.