Zilpaterol is a β-adrenergic receptor agonist that putatively through activation of protein kinase A increases protein synthesis in skeletal muscle fibers, as well as reduces lipogenesis and increases lipolysis in adipose tissues.^1,2It was approved by the FDA in 2006 as a veterinary food additive for the purpose of increasing lean body weight and improving feed efficiency in commercial beef cattle.³

1.AvendaÑo-Reyes, L., Torres-RodrÍguez, V., Meraz-Murullo, F.J., et al.Effects of two β-adrenergic agonists on finishing performance, carcass characteristics, and meat quality of feedlot steersJ. Anim. Sci.84(12)3259-3265(2006) 2.Miller, E.K., Chung, K.Y., Hutcheson, J.P., et al.Zilpaterol hydrochloride alters abundance of β-adrenergic receptors in bovine muscle cells but has little effect on de novo fatty acid biosynthesis in bovine subcutaneous adipose tissue explantsJ. Anim. Sci.90(4)1317-1327(2012) 3.Delmore, R.J., Hodgen, J.M., and Johnson, B.J.Perspectives on the application of zilpaterol hydrochloride in the United States beef industryJ. Anim. Sci.88(8)2825-2828(2010)