Analysing plant-based food supplements is particularly challenging due to their complexcomposition. The inclusion of multiple plant species in a single product often results inoverlapping or interfering signals when conventional chromatographic methods are used. Toovercome these limitations, a novel approach was applied, integrating chromatographicfingerprinting with chemometric analysis and employing a multi-wavelength detectionstrategy to improve resolution and accuracy. Binary classification models were built to identifythe presence or absence of regulated plant materials in the samples. These models achievedstrong performance and were validated through both cross-validation and external test sets,ensuring the robustness of the results. A targeted market study of 25 samples arising fromillegal sources was carried out, uncovering several noteworthy and concerning findings. Thisstudy focused on supplements marketed for potency enhancement, often linked tounregulated or illicit sources. The results revealed a significant occurrence of herbaladulteration, highlighting the urgent need for systematic screening protocols and stricterregulatory measures.