Tier 3 — preclinical

Comparative Analysis of L-Carnitine and Coenzyme Q10 Adverse Reaction Reports Using the EudraVigilance Database: Implications for Health and Sports Supplementation

Debora Di Mauro, Fabrizio Calapai, Ilaria Ammendolia, Mariaconcetta Currò, Fabio Trimarchi, Carmen Mannucci
Nutrients 2026 18(11):1716

Bibliography

PubMed
PMID 42280358
PubMed Central
PMC13258800
DOI
10.3390/nu18111716
Funding
The authors reported that the research received no external funding.
Competing interests
The authors declared no conflicts of interest.

Study snapshot

DesignRetrospective pharmacovigilance analysis of spontaneous individual case safety reports with disproportionality analysis
ModelEudraVigilance reports from the European Economic Area and United Kingdom
Sample271 CoQ10 individual case safety reports; 257 L-carnitine reports used as comparator
InterventionNo assigned intervention; spontaneous reports involving CoQ10/ubiquinone/ubidecarenone entered through 31 December 2025
DurationDatabase reports through 31 December 2025; data extracted 10 February 2026
EndpointsSerious versus non-serious individual case safety reports; System Organ Class reporting patterns; Reporting odds ratio; Proportional reporting ratio

What the study showed, in plain terms

This 2026 study analyzed spontaneous adverse-reaction reports in EudraVigilance rather than participants enrolled in a clinical trial. Researchers identified 271 CoQ10 reports and compared their reporting patterns with 257 L-carnitine reports.

Among the CoQ10 reports, 202 were classified as serious and 69 as non-serious. General disorders, nervous-system disorders, investigations and gastrointestinal disorders were among the more commonly reported system categories.

These percentages are not an adverse-event rate among CoQ10 users. Spontaneous-report databases have no reliable denominator for how many people used the supplement, are vulnerable to reporting bias and confounding, and cannot establish that CoQ10 caused an event. The findings are safety signals for further study, not proof that CoQ10 is unusually dangerous.

Key findings

271 CoQ10 spontaneous safety reports were identified; 202 were classified as serious and 69 as non-serious.

Compared with L-carnitine reports, CoQ10 had higher disproportionality signals for blood/lymphatic disorders (ROR 3.04; PRR 2.99) and musculoskeletal/connective-tissue disorders (ROR 2.63; PRR 2.52).

The authors explicitly caution that spontaneous-report data cannot establish incidence, absolute risk or causality.

What this study can and cannot tell us

No exposure denominator: the study cannot calculate how often adverse reactions occur among CoQ10 users.

Spontaneous reports are affected by underreporting, stimulated reporting, incomplete medical histories, concomitant drugs and uncertain causality.

The comparator was L-carnitine rather than a matched untreated population, so disproportionality signals are hypothesis-generating and should not be described as comparative toxicity rates.

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology