Chlorogenic acids and caffeine in commercial green coffee bean extract supplements: quantitative assessment and evidence of mislabelling

Green coffee bean extract (GCBE) supplements are widely marketed for weight management, primarily due to their chlorogenic acids (CGAs) and caffeine content. This study evaluated the authenticity and quality of 23 commercial GCBE products by quantifying three major CGA isomers (3-CQA, 4-CQA and 5-CQA) and caffeine using HPLC-DAD. The CGA content ranged from non-detectable to 31.15%, with 5-CQA being predominant. Caffeine levels varied from non-detectable to 3.82%. Notably, two samples labelled as containing 50% CGAs had none detected, while several 'decaffeinated' products exceeded regulatory caffeine thresholds. Only three samples declared caffeine levels, none of which were fully compliant with their labels. Hierarchical cluster analysis (HCA) grouped the supplements into four distinct clusters based on total CGA and caffeine content, revealing widespread inconsistencies. These findings raise concerns over mislabelling, regulatory non-compliance, and potential health risks, underscoring the urgent need for stricter quality control and accurate labelling in the dietary supplement industry.