Buyers should request stability test reports to verify a shelf life of typically 18 to 24 months. To evaluate effectiveness, ask for the active ingredient content (e.g., polyphenols, flavonoids, or specific herbal extracts). It is highly recommended to order samples to conduct sensory evaluations, focusing on aroma, clarity of the liquor, and taste profile. For functional teas (e.g., detox, slimming, or sleep aid), verify if the supplier has proprietary formulas or if they offer customized blending services based on traditional pharmacopeia.