Safety Considerations for Natural Products with Adaptogenic and Immunomodulating Activities

Background/Objectives: Natural products with claimed adaptogenic and/or immunomodulatory effects are widely used in traditional medicine systems across Eurasia. These include herbal remedies (e.g., Panax ginseng), fungi (e.g., Ganoderma lucidum), and animal-derived substances (e.g., propolis from Apis mellifera). Despite their popularity, the safety profiles of these products-particularly concerning adverse events (AEs) and serious adverse events (SAEs)-remain insufficiently understood. This study aimed to assess the safety profiles of adaptogenic and immunomodulatory natural products through a scoping review of published human studies and an analysis of individual case safety reports (ICSRs) from the WHO-UMC VigiBase database. Methods: A scoping review was conducted using PubMed (1980-2024) in line with PRISMA-ScR guidelines. Eligible studies included randomized and non-randomized clinical trials and case reports in humans focused on safety outcomes. Data extraction followed the Joanna Briggs Institute (JBI) standardized template. ICSRs from VigiBase were analyzed by product type, AE type and seriousness, and demographic characteristics. The data were further organized to highlight the 15 most frequently reported products and their top five System Organ Classes (SOCs) and Preferred Terms (PTs). Results: The scoping review identified 51 natural products with reported adaptogenic and/or immunomodulatory properties. This included 285 clinical trials and 119 case studies on single-ingredient products and 54 clinical trials and 21 case studies on multi-ingredient preparations. Common AEs included gastrointestinal, dermatological, hepatic, cardiovascular, and immunological reactions. SAEs were rare but reported for Echinacea purpurea, Silybum marianum, and Camellia sinensis. From Vigibase, 45,042 ICSRs were retrieved for 49 natural products: 10,702 for single-ingredient and 34,340 for multi-ingredient products. Among 7856 reports listing a single-ingredient product as the sole suspect, 15.8% were SAEs, including eight fatal cases. However, the causality remained unclear due to insufficient data. Ganoderma lucidum, Viscum album, and Silybum marianum were most frequently associated with SAEs. In multi-ingredient products, propolis was frequently linked to hypersensitivity and skin reactions. Conclusions: This study provides a comprehensive overview of the safety profiles of adaptogenic and immunomodulatory natural products. Variability in product composition, lack of standardization, incomplete reporting in clinical studies, and underreporting in pharmacovigilance databases complicate accurate risk assessment. For multi-ingredient products, attributing specific AEs to specific components remains difficult. Further high-quality clinical research and improved pharmacovigilance are needed, along with clear safety warnings to reduce risks for consumers.