Buyers must prioritize purity levels, typically requiring ≥98% or ≥99% as determined by HPLC (High-Performance Liquid Chromatography). It is essential to distinguish between Monosodium AKG, Calcium AKG (Ca-AKG), and Potassium AKG, as Ca-AKG is the most popular for longevity supplements due to its stability and slower absorption rate. Additionally, check for heavy metal limits (Lead <0.5ppm, Arsenic <0.5ppm) and microbiological standards (Total Plate Count <1000cfu/g) to ensure pharmaceutical or food-grade quality.