When sourcing Tktx Numb Cream, the primary focus must be on the active ingredient concentration (typically Lidocaine, Prilocaine, and Epinephrine). Buyers should verify the percentage of numbing agents to ensure they meet the specific needs of the application, such as tattooing, microblading, or laser treatments. It is essential to request a Certificate of Analysis (COA) to confirm the chemical composition and ensure the product provides the promised duration of anesthesia, which usually ranges from 2 to 5 hours depending on the specific color-coded formula (e.g., Gold, Black, or Blue).