Potential Toxicological Risk Associated with the Oral Use of Colloidal Silver Dietary Supplements

Abstract

The increasing availability of colloidal silver dietary supplements raises important concerns regarding their safety when used for oral consumption. This study presents the physicochemical characterization of a commercial colloidal silver solution with a high concentration (1000 mg/L), stabilized with pectin in distilled water. The characterization was performed using UV-VIS, XRD, and TEM. The manufacturer did not provide information regarding nanoparticle size or recommended duration of use. The 1000 mg/L sample was also compared with a standard colloidal silver solution provided by Sigma Aldrich to validate nanoparticle size, stability, and spectral profiles. In addition, a comparative theoretical analysis was conducted on other commercially available products containing colloidal silver at concentrations of 15, 30, 55, 80, and 125 mg/L, based solely on the recommended daily intake and the oral reference dose of 0.005 mg/kg/day established by the United States Environmental Protection Agency (EPA). Although no in vivo or in vitro toxicity tests were performed, the results indicate a potential toxicological risk due to estimated intake levels that may exceed safety thresholds, particularly in high-concentration products with insufficient labelling or unclear usage guidelines. These findings emphasize the need for stricter regulatory measures and greater public awareness regarding the internal use of colloidal silver supplements.