ACTH (1–39), or Adrenocorticotropic Hormone (1–39), is a 39-amino-acid peptide secreted by the anterior pituitary gland as part of the body’s response to stress. It plays a central role in activating the adrenal cortex to produce and release glucocorticoids, particularly cortisol, which are essential for energy metabolism, immune modulation, and homeostatic regulation.

The full-length sequence of ACTH (1–39) retains all biological activity, making it highly suitable for studies exploring HPA axis dynamics, adrenal responsiveness, and neuroendocrine signaling. In research models, ACTH (1–39) is used to assess adrenal function, model stress-induced hormonal pathways, and investigate glucocorticoid-mediated physiological effects.

Its applications extend to investigations of inflammatory responses, circadian hormone rhythms, and adrenal insufficiency. Due to its precise action on melanocortin 2 receptors (MC2R) in the adrenal cortex, ACTH (1–39) remains a valuable tool in both basic and applied endocrine research.