Function
While Acetyl tetrapeptide-5 is used in cosmetic eye formulations to decrease puffiness, eye bags, and dark circles by reducing edema and protecting proteins such as SOD from glycation51150159154, Selank is a peptide developed in Russia as an anxiolytic and nootropic; in animal models it reduces anxiety-like behavior and modulates immune parameters under stress39.
Mechanism
While Acetyl tetrapeptide-5 works as a synthetic tetrapeptide, Ac-βAla-His-Ser-His (Eyeseryl), with reported ACE-1 inhibition and anti-glycation activity, proposed to improve microcirculation and reduce capillary permeability and fluid accumulation in periorbital tissues51150159157, Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, that combines a tuftsin fragment with a Pro-Gly-Pro motif and is reported to modulate GABAergic neurotransmission and cytokine balance while being resistant to proteolytic degradation39.