Mannitol is widely used in pharmaceutical, food, and chemical industries, so compliance is critical. For pharmaceutical grade (API), ensure the supplier meets USP (US Pharmacopeia), EP (European Pharmacopoeia), or BP (British Pharmacopoeia) standards. For food grade, look for FCC (Food Chemicals Codex) compliance, along with ISO 22000, HACCP, Halal, and Kosher certifications. Always request a Certificate of Analysis (COA) for every batch to verify purity levels, which should typically be 98.0% to 102.0%.