Dietary supplements are intended to enrich daily diet. Dietary supplements containing ingredients of plant origin are particularly often chosen because they are perceived as natural and safe. In reality, however, their safety and quality raise many objections. The aim of the study was the analysis of the caffeine content in weight-loss dietary supplements, which are widespread on the Polish market. Five dietary supplements and one medicinal product were included in the study.

Ultrasound-assisted extraction was used in the work. Samples of the analyzed formulations were extracted with water. The obtained extracts were subjected to quantitative analysis using high performance liquid chromatography HPLC.

In most cases, the determined caffeine content was different from the value declared by the manufacturer. In three cases this content was lower and in one preparation higher in relation to the manufacturer’s declaration. These differences were statistically significant.

Keywords: dietary supplements, caffeine, weight-loss.