Ractopamine is a feed additive to promote leanness in animals raised for their meat. Pharmacologically, it is a TAAR1 agonist and β adrenoreceptor agonist that stimulates β1 and β2 adrenergic receptors. Ractopamine is known to increase the rate of weight gain, improve feed efficiency, and increase carcass leanness in finishing swine. Its use in finishing swine yields about three kilograms of additional lean pork and improves feed efficiency by 10%. Ractopamine is the active ingredient in products known as Paylean for swine and Optaflexx for cattle, developed by Elanco Animal Health, a division of Eli Lilly and Company, for use in food animals for growth promotion. Ractopamine use has been banned in most countries, including the European Union, mainland China and Russia while 27 other countries, such as Japan, the United States, Canada, and South Korea, have deemed meat from livestock fed ractopamine safe for human consumption. Ractopamine is safe for finishing pigs heavier than 240 lb (110 kg) when administered in the diet at concentrations up to 10 ppm and fed for up to 35 days.