They bind to specific receptors on target cells and trigger defined biological responses
Right now, though, oral tirzepatide is not FDA-approved, and injectable forms remain the most reliable and well-studied option available
Many are available over the counter (OTC)
A weekly formulation of exenatide called Bydureon was approved in 2012
J Interferon Cytokine Res 31:653659 Malaguarnera M, Vacante M, Giordano M, Pennisi G, Bella R, Rampello L, Malaguarnera M, Li Volti G, Galvano F (2011) Oral acetyl-l-carnitine therapy reduces fatigue in overt hepatic encephalopathy: a randomized, double-blind, placebo-controlled study