Real-world pharmacovigilance data suggest partially different ADR reporting patterns for L-carnitine and CoQ10 compared with those described in pre-marketing studies, with CoQ10 associated with a higher proportion of serious reports and greater disproportionality signals for selected system organ class categories.
A total of 257 individual case safety reports (ICSRs) were identified for L-carnitine and 271 for CoQ10 in the EudraVigilance database.
Serious adverse drug reaction cases accounted for a substantially higher proportion of CoQ10 reports (74.5%) compared to L-carnitine reports (34.2%).
For L-carnitine, the most frequently reported SOC categories were gastrointestinal disorders, skin and subcutaneous tissue disorders, general disorders and administration site conditions, and nervous system disorders.
For CoQ10, the most commonly reported SOC categories were general disorders and administration site conditions, nervous system disorders, investigations, and gastrointestinal disorders.
Comparative disproportionality analysis showed higher reporting frequencies for CoQ10 in blood and lymphatic system disorders and musculoskeletal and connective tissue disorders.
The real-world pharmacovigilance ADR profiles of both L-carnitine and CoQ10 differ partially from those described in pre-marketing studies.
This research examined real-world safety reports for two popular dietary supplements — L-carnitine and Coenzyme Q10 (CoQ10) — using the EudraVigilance database, which collects reports of adverse drug reactions from across Europe. The researchers found 257 reports for L-carnitine and 271 for CoQ10, and discovered that the types of side effects reported in the real world differ somewhat from what was described in earlier clinical trials. Notably, CoQ10 was linked to a much higher proportion of serious adverse events (74.5%) compared to L-carnitine (34.2%), and showed stronger statistical signals for blood/lymphatic system disorders and musculoskeletal problems. L-carnitine's most common reported issues involved the gut and skin, while CoQ10's most common reports involved general body symptoms, nervous system effects, and abnormal laboratory findings. This research suggests that even supplements widely regarded as safe may carry meaningful risks in some users, and that pre-market safety studies alone may not capture the full range of adverse effects seen in the broader population. The finding that CoQ10 was associated with a disproportionately high rate of serious reports is particularly noteworthy, though the authors caution that this could reflect differences in who uses the supplement (e.g., people with pre-existing illnesses), reporting tendencies, or use alongside medications rather than the supplement itself causing harm. The practical implication of this study is that both L-carnitine and CoQ10, despite being available without a prescription and commonly used by athletes and patients alike, warrant continued safety monitoring. This research suggests that healthcare providers and consumers should be aware that real-world use can be associated with a broader range of side effects than those listed in product labeling, and that ongoing surveillance through databases like EudraVigilance is important for understanding the true safety profile of widely used supplements.
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Upload Your LabsDi Mauro D, Calapai F, Ammendolia I, Currò M, Trimarchi F, Mannucci C. (2026). Comparative Analysis of L-Carnitine and Coenzyme Q10 Adverse Reaction Reports Using the EudraVigilance Database: Implications for Health and Sports Supplementation.. Nutrients. https://doi.org/10.3390/nu18111716