Ractopamine

Ractopamine is an animal feed additive used to increase leanness and improve feed conversion efficiency in farmed animals, developed by Elanco Animal Health and sold in the United States under brand names including Paylean for swine, Optaflexx for cattle and Topmax for turkeys. It is a phenol-based TAAR1 agonist and beta-adrenergic agonist that stimulates specific adrenergic receptors, and as of 2025 it is banned or restricted in 168 countries, including the European Union, China and Russia, though it remains legal in the United States, with a maximum residue limit of 50 parts per billion in pork, as well as in Japan, Taiwan, South Korea and New Zealand under their own limits. The substance has become a point of international trade disputes and has also figured in doping cases in sport, where meat containing ractopamine residue raised questions about accidental violations of anti-doping rules.