Quality evaluation depends on the species (Panax ginseng vs. Panax quinquefolius), age, and processing method. Buyers should prioritize 6-year-old roots, as they typically contain the highest concentration of ginsenosides, the active pharmacological component. For Red Ginseng, check for a uniform reddish-brown color and a firm, translucent texture. For White Ginseng, ensure the roots are well-dried with a moisture content below 12% to prevent mold. Always request a Certificate of Analysis (CoA) to verify the ginsenoside content and the absence of heavy metals.