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Safety assessment of coenzyme Q10 (Kaneka Q10) in healthy subjects: a double-blind, randomized, placebo-controlled trial

Hideyuki Ikematsu, Kenjiro Nakamura, Shin-ichi Harashima, Kenji Fujii, Naoki Fukutomi
Regulatory Toxicology and Pharmacology 2006 44(3):212-218

Bibliography

PubMed
PMID 16431002
DOI
10.1016/j.yrtph.2005.12.002
Funding
The study tested the branded Kaneka Q10 ingredient and included Kaneka Corporation personnel among the authors. A separate modern-style funding statement was not identified in the accessible publication record.
Competing interests
Authors included Kaneka Corporation personnel, including Kenji Fujii and Naoki Fukutomi, and the tested product was Kaneka Q10. This manufacturer relationship should be considered when interpreting the safety conclusions.

Study snapshot

DesignDouble-blind randomized placebo-controlled dose-ranging safety trial.
ModelHealthy adults; 55 men and 33 women enrolled.
Sample88 volunteers, approximately 22 per group. Three participants were excluded from analysis for intercurrent events: two placebo and one 300 mg participant.
InterventionKaneka Q10 capsules at 300, 600 or 900 mg/day versus placebo for four weeks.
Duration4 weeks of dosing with clinical/laboratory safety monitoring.
EndpointsAdverse events; Serious adverse events; Hematology; Blood chemistry; Urinalysis; Plasma CoQ10; Dose-dependency of safety signals

What the study showed, in plain terms

This randomized safety study assigned 88 healthy adults to placebo or Kaneka Q10 at 300, 600 or 900 mg/day for four weeks. It was designed to look for tolerability problems and laboratory toxicity rather than clinical benefit.

No serious adverse events occurred. Adverse events were reported by 16 placebo participants, 12 receiving 300 mg/day, 20 receiving 600 mg/day and 16 receiving 900 mg/day. Common events included cold symptoms and gastrointestinal complaints such as abdominal pain and soft stools. The investigators reported no dose-dependent adverse-event pattern and judged these events unrelated to Kaneka Q10.

Changes in hematology, blood chemistry and urinalysis were not dose-related and were not considered clinically significant. These data support short-term tolerability up to 900 mg/day in selected healthy adults, but four weeks is far too short to establish long-term safety, rare adverse effects or safety in pregnancy/complex disease.

Key findings

  • No serious adverse events were observed in any group.
  • Participants reporting adverse events: placebo 16; 300 mg/day 12; 600 mg/day 20; 900 mg/day 16.
  • Common events included cold symptoms, abdominal pain and soft feces; no dose-dependent pattern was identified.
  • Hematology, blood chemistry and urinalysis changes were not dose-related and were judged not clinically significant.
  • Three participants were excluded from the primary analysis for intercurrent events (two placebo, one 300 mg), while one placebo participant with acute colitis remained included despite reduced adherence.

What this study can and cannot tell us

  • Only four weeks of treatment; cannot establish chronic or rare-event safety.
  • Healthy volunteers were selected to exclude serious disease and relevant medication/supplement use; findings may not apply to medically complex users.
  • The study tested a manufacturer-branded ingredient and included Kaneka Corporation personnel among the authors.
  • Absence of a dose-related laboratory signal does not establish safety in pregnancy, lactation, children, severe organ disease or drug-interaction settings.

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