GMP (Good Manufacturing Practice) is a set of regulatory standards, enforced by agencies like the FDA, that govern how medications must be produced, tested, and quality-controlled to ensure consistency, purity, and safety. Facilities that manufacture GLP-1 medications, and legitimate compounding pharmacies, are expected to meet GMP standards — a useful question to ask when evaluating whether a source for a medication is legitimate, especially compared to unregulated grey market sellers that operate outside these standards.