Pharmaceutical-grade peptides (like brand-name Mounjaro or Wegovy) are manufactured under strict FDA-regulated GMP conditions with guaranteed purity, sterility, and potency. Research-grade peptides are sold "for research purposes only" and are not subject to the same manufacturing oversight. Purity can vary widely—some are excellent, some contain impurities or are underdosed. This is exactly why independent testing matters: you can't assume research-grade products meet pharmaceutical standards without verifying.