Coenzyme Q10 (
CoQ10) provides the energy for vital cellular functions and is known to act as an
antioxidant. We conducted an open label study to examine the clinical effects of supplementation of the reduced form of
CoQ10,
ubiquinol, in addition to conventional
glucose-lowering agents in patients with
type 2 diabetes. Nine subjects (3 males and 6 females) with
type 2 diabetes and receiving conventional medication were recruited. The subjects were assigned to receive an oral dose of 200 mg
ubiquinol daily for 12 weeks. The effect of
ubiquinol on blood pressure,
lipid profile,
glycemic control, oxidative stress, and
inflammation were examined before and after
ubiquinol supplementation. In addition, five healthy volunteers were also assigned to receive an oral dose of 200 mg
ubiquinol daily for 4 weeks to examine the effects of
ubiquinol on insulin secretion. In patients with diabetes, there were no differences with respect to blood pressure,
lipid profile, oxidative stress marker, and inflammatory markers. However, there were significant improvements in
glycosylated hemoglobin (53.0 ± 4.3 to 50.5 ± 3.7 mmol/mol, P = 0.01) (7.1 ± 0.4 to 6.8 ± 0.4%, P = 0.03). In healthy volunteers, the insulinogenic index (0.65 ± 0.29 to 1.23 ± 0.56, P = 0.02) and the ratio of
proinsulin to
insulin were significantly improved (3.4 ± 1.8 to 2.1 ± 0.6, P = 0.03). The results of our study are consistent with the suggestion that the supplementation of
ubiquinol in subjects with
type 2 diabetes, in addition to conventional
antihyperglycemic medications, improves
glycemic control by improving insulin secretion without any adverse effects