Endogenous agonist at orexin receptors (Ki values are 20 and 38 nM for OX1 and OX2 receptors respectively). Stimulates feeding following central administration and may be involved in the control of sleep-wake cycle and other hypothalamic functions.

QS-21, an immunostimulatory saponin, is a powerful vaccine adjuvant that stimulates both Th2 humoral and Th1 cell-mediated immune responses by interacting with antigen presenting cells (APCs) and T cells.

4-Propionamidophenol is a p-acetamidophenol analog.