Preventing a Public Health Issue by Quantification of Illegally Added Sexual Enhancers in Natural Dietary Supplements

The lack of regulation for "natural" dietary supplements raises public health concerns as they may contain undisclosed active ingredients, without proper labelling. Natural libido boosters, marketed as dietary supplements for male sexual function improvement, have been linked to serious side effects, prompting health authorities to issue warnings. Liquid chromatography coupled to mass spectrometry (LC-MS) methods are commonly used to detect non-regulated substances in these supplements. In the present work, an LC-MS/MS method was validated to verify that it provides robust and reliable results, with enough sensitivity (LOD ≤ 10 µg·kg-1 and LOQ ≤ 45 µg·kg-1), precision (RSD ≤ 15%), and accuracy (80–120% recovery). Then, the concentration of sildenafil, tadalafil, vardenafil, yohimbine and desmethyl carbodenafil was evaluated in several dietary supplements commercially available in Spain. 17 samples were analyzed, and 4 presented contaminations of sildenafil, yohimbine or tadalafil. The outstanding results lead to a robust analytical method that can be used to detect and prevent fraud, ensure food security and prevent public health issues.