This study presents the development of a sustainable analytical method using high-performance liquid chromatography (HPLC) for determination and quantification of bioactive compounds in Herbal Dietary Supplements (HDS) solid oral formulations containing green tea (Camellia sinensis). Four compounds [gallic acid, (+)-catechin, caffeine and caffeic acid] were determined in fifteen HDS samples (capsules and tablets) containing green tea marketed in Brazil. After optimizing the extraction process using factorial planning and response surface analysis, it was possible to develop the method. Methanol and acetic acid (0.25%) were components of the mobile phase, showing it as a more sustainable alternative to the use of acetonitrile. The samples evaluated demonstrated a lack of standardization in the concentrations (in mg g−1) of the chemical markers studied gallic acid (<LOD to 1.39), (+)-catechin (<LOD to 13.8), caffeine (<LOQ to 22) and caffeic acid (<LOD to 1.7). This concern has driven significant scientific research on the topic. The chromatographic method proved to be effective, sensitive and robust for qualification and quantification of the 4 chemical markers studied. This study found variations in the levels of chemical markers in HDS containing green tea sold in Brazil. Therefore, it can contribute to the regulation and quality control of these solid oral products (capsules and tablets) containing this plant.