Tretinoin is a regulated pharmaceutical substance. Suppliers must provide GMP (Good Manufacturing Practice) certification and, ideally, a Drug Master File (DMF) number. For entry into major markets, ensure the product meets USP (United States Pharmacopeia) or EP (European Pharmacopoeia) standards. If purchasing finished creams or gels, the manufacturer must hold a Medical Device or Cosmetic Production License depending on the local classification, and provide MSDS (Material Safety Data Sheets) for shipping.