Abstract
The safety of coenzyme Q10 (CoQ10) at a high dose of 900 mg/day was assessed by a randomized, double-blind, placebo-controlled study. Twenty subjects were assigned to the CoQ10 supplemented group (CoQ10 group) and the other 20 subjects to the placebo group. Hard capsules containing CoQ10 and placebo were ingested daily by the respective groups at a dose of 900mg/day for 4 weeks. Minute changes in several test items were observed in physical examination, hematological and blood biochemical analysis, and urinalysis in the dose of CoQ10 and placebo. However, these changes were within normal ranges and thus considered not to be clinically significant. During the ingestion period, the following adverse events were noted in the CoQ10 group: soft feces and/or diarrhea (2 cases), constipation (one case), common cold (2 cases), dizziness (one case), headache (one case), stiff shoulder (one case), and stomachache (one case). In the placebo group, the following adverse events were noted: diarrhea (one case), headache (one case), nausea (one case), and common cold (2 cases). However, these events were temporal, slight, and limited to a small population. Moreover, no abnormalities were detected by the medical examination. Therefore, it was concluded that CoQ10 was well-tolerated and safe for healthy adults at a dose of 900mg/day for 4 weeks under the condition of the study.
